Techniques of Crime Scene Investigation

Author: Barry A. J. Fisher | David Fisher

617 downloads 4442 Views 17MB Size Report

This content was uploaded by our users and we assume good faith they have the permission to share this book. If you own the copyright to this book and it is wrongfully on our website, we offer a simple DMCA procedure to remove your content from our site. Start by pressing the button below!

Report copyright / DMCA form

DOWNLOAD PDF

S E V E N T H

E D I T I O N

Techniques of

CRIME SCENE INVESTIGATION

© 2004 by CRC Press LLC

S E V E N T H

E D I T I O N

Techniques of

CRIME SCENE INVESTIGATION Barry A. J. Fisher Crime Laboratory Director Los Angeles County Sheriff’s Department Los Angeles, California with a foreword by Leroy D. Baca Sheriff of Los Angeles County

CRC PR E S S Boca Raton London New York Washington, D.C.

© 2004 by CRC Press LLC

Library of Congress Cataloging-in-Publication Data Fisher, Barry A. J. Techniques of crime scene investigation / Barry A.J. Fisher ; with a foreword by Leroy D. Baca.—7th ed. p. cm. Includes bibliographical references and index. ISBN 0-8493-1691-X (alk. paper) 1. Crime scene searches. 2. Criminal investigation. I. Title. HV8073.F49 2003 363.25'2—dc21 2003047262

This book contains information obtained from authentic and highly regarded sources. Reprinted material is quoted with permission, and sources are indicated. A wide variety of references are listed. Reasonable efforts have been made to publish reliable data and information, but the author and the publisher cannot assume responsibility for the validity of all materials or for the consequences of their use. Neither this book nor any part may be reproduced or transmitted in any form or by any means, electronic or mechanical, including photocopying, microﬁlming, and recording, or by any information storage or retrieval system, without prior permission in writing from the publisher. The consent of CRC Press LLC does not extend to copying for general distribution, for promotion, for creating new works, or for resale. Speciﬁc permission must be obtained in writing from CRC Press LLC for such copying. Direct all inquiries to CRC Press LLC, 2000 N.W. Corporate Blvd., Boca Raton, Florida 33431. Trademark Notice: Product or corporate names may be trademarks or registered trademarks, and are used only for identiﬁcation and explanation, without intent to infringe.

Visit the CRC Press Web site at www.crcpress.com © 2004 by CRC Press LLC No claim to original U.S. Government works International Standard Book Number 0-8493-1691-X Library of Congress Card Number 2003047262 Printed in the United States of America 1 2 3 4 5 6 7 8 9 0 Printed on acid-free paper

© 2004 by CRC Press LLC

Dedication This book is dedicated to the unsung heroes of the criminal justice system — those men and women who through the application of science and technology bring criminals to justice and protect those wrongfully accused.

© 2004 by CRC Press LLC

Foreword

Forensic science has been an ally of law enforcement agencies for decades. That relationship has grown even stronger with the startling new advancements in science and technology. Law enforcement agencies throughout the world rely heavily on forensic science to assist in solving the most complex crimes while sorting out elaborate crime scenes. To an untrained eye, many of these crime scenes appear to contain little or no evidence. However, upon closer inspection by these highly skilled, trained professionals, unseen evidence — hair, skin, bodily ﬂuids, microscopic ﬁbers, and traces of seemingly insigniﬁcant items are revealed as important pieces of the puzzle. The long arm of the law becomes even longer in large measure because of the dedication and commitment of these forensic professionals. Needless to say, law enforcement owes a debt of gratitude to the forensic professionals working on our team. We enjoy a very productive relationship with experts in all the areas of forensic science and crime scene investigations: ﬁngerprint identiﬁcation, forensic photography, questioned documents, ﬁrearms, toxicology, narcotics analysis, forensic DNA testing, and trace evidence examination. The Los Angeles County Sheriff ’s Department has been especially fortunate to have Barry A.J. Fisher as the director of our Scientiﬁc Services Bureau, one of the largest municipal crime laboratories in the nation. I am honored to offer this brief commentary for his latest publication, the seventh edition of Techniques of Crime Scene Investigation. His unfettered and candid pledge to the ﬁeld of forensic science is evident in this latest edition. This volume also highlights some of the latest techniques of forensic science and discusses our latest concerns in handling potential terrorism crime scenes that may contain chemical or biological agents and evidence. The Los Angeles County Sheriff ’s Department is fortunate to have leaders like Barry Fisher, who consistently strives to initiate advancements in his areas of expertise and educate others to radiate the same commitments and traditions. Leroy D. Baca Sheriff of Los Angeles County

© 2004 by CRC Press LLC

Preface

Readers may ask why I wrote a new edition; after all, crime scene investigation is a static ﬁeld with few changes. True enough. There have been DNA advances and other developments in forensic science. However, new practitioners and students of crime scene investigations and forensic science must be aware of two increasingly important issues: increasing judicial reviews of science and technology in the courtroom and the specter of terrorism and weapons of mass destruction with which ﬁrst responders, forensic scientists and medical examiners will be faced. September 11, 2001, has shown us that the unthinkable is indeed possible. Having said all this, criminal investigations remain a complex undertaking and require professionals from many disciplines to work cooperatively toward one common goal. The effective use of science and technology is a critical element to crime solving. Police investigators and prosecutors must be able to use this resource to its full potential. Science and technology applied to the solution of criminal acts — forensic science — solve crimes and potentially save lives. Scientiﬁc crime scene investigation aids police investigators in identifying suspects and victims of crimes, clearing innocent persons of suspicion and ultimately bringing the wrongdoers to justice. When the justice system is able to remove a criminal from society, innocent persons do not become new victims of criminal acts. This book is about the proper and effective use of science and technology in support of the police. The seventh edition of Techniques of Crime Scene Investigation is written for students of crime scene investigation, police investigators, crime scene technicians, and forensic scientists. The material presented in this text is basic, covering the proper ways to examine crime scenes and collect a wide variety of physical evidence that may be encountered at crime scenes. It cannot cover every possible situation and is a guide. The areas are discussed in general terms in order to give the reader some idea of the information that can be developed from physical evidence if it is collected properly. Few of the procedures mentioned in the book are inviolable. Techniques of Crime Scene Investigation is a classic book on how to use forensic science to investigate crimes. The text was ﬁrst published in Swedish in 1949 by Chief Superintendent Arne Svensson, director of the Laboratory, Criminal Investigation Department, and Superintendent Otto Wendel, Criminal Investigation Department, Stockholm, Sweden. In 1955 it was printed in English as Crime Detection and then revised into a second, expanded American Edition under the title Techniques of Crime Scene Investigation in 1965. In 1981 I was invited to revise it in a third edition and subsequently into fourth, ﬁfth, and sixth editions. This seventh edition is the ﬁfth revision I have had the privilege to write. The latest edition of Techniques of Crime Scene Investigation continues a half-century tradition of providing useful techniques, procedures and suggestions on how to locate, document, collect and process physical evidence associated with criminal acts. This edition

© 2004 by CRC Press LLC

continues in that tradition. It updates some of the new areas in the ﬁeld and covers some new topics while keeping intact those areas that have not changed greatly. I have also added some new photographs to illustrate certain areas of the text. Some of the topics included in this edition include: • • • • • • • •

Discussion on professional ethics Challenges facing forensic science laboratories and suggestions for addressing them Expert witness testimony Health and safety issues at crime scenes Forensic DNA testing Forensic databases Elder abuse Forensic science and terrorist acts

Another feature new to this edition is a companion CD developed by Dr. Jane Homeyer and Sarah Mikolajczyk: CAT3, Creative Approaches to Teaching, Training & Testing, Inc. This new concept of a traditional textbook with a CD that mirrors the major topics represents a 21st century approach to learning that we hope is seen as a big plus for our readers. The CD can be purchased directly from CRC Press. The use of forensic science in criminal investigations depends on a number of factors. Police investigators must be knowledgeable about the capabilities of the forensic science support services available to them and appreciate how to use them effectively. Forensic practitioners must be familiar with police investigative procedures, the science that supports their own activities, and the legal aspects needed to get the information from the scene and in the lab to the jury. Prosecutors must understand the scientiﬁc and technological issues of the case and be able to work with the expert in order to admit expert testimony into court. Police agencies that run forensic science labs must fund them at an appropriate level to ensure quality, reliable, and timely service to the criminal justice system. All of these efforts require the cooperation and willingness of different professionals within the criminal justice system to work well together. Those of us who apply science and technology to the solution of crimes have a duty to do our best for the criminal justice system we serve.

© 2004 by CRC Press LLC

Acknowledgments

In preparation of this seventh edition, I contacted colleagues for interesting cases for inclusion in it. Although I was not able to use all of their submissions, I want to thank all who responded to my request for cases for this edition. If I have failed to include you in this listing, I apologize for the oversight: Don Keir, John Shaw, Roger Yung, Mike Havstad, and Yvette Stewart, Scientiﬁc Services Bureau, Los Angeles County Sheriff ’s Department, Los Angeles, CA; Pam Hofsass, Inspector, San Francisco Police Department, Forensic Services Division, San Francisco, CA; Ray Wickenheiser, Laboratory Director, and Doug Lancon, Acadiana Criminalistics Laboratory, New Iberia, LA; Ted Silenieks, Evidence Recovery Section, and Hilton Kobus, Laboratory Director, South Australia Forensic Science Centre, Adelaide, South Australia; Sgt. Paul Sheldon, Crime Scene Investigator, South Australian Police, Adelaide, South Australia; Rick Mancilla, Limbic Systems Inc., Bellingham, WA; C. Michael Bowers, DDS, JD, Ventura, CA; Neil Holland; Forensic Document Examiner, Melbourne, Victoria, Australia; Baruch Glattstein, Division of Identiﬁcation and Forensic Science, Israel National Police, Jerusalem, Israel; Norman D. Sperber, DDS, San Diego, CA; S.C. Leung, Director, Government Laboratory, Hong Kong. I also wish to thank my many friends and colleagues who submitted cases and photographs for prior editions of this book. Many of these are shown again in this edition; acknowledgements for those submissions were made in past editions. I wish to acknowledge the kind support of the Los Angeles County Sheriff ’s Department and, particularly, Sheriff Leroy D. Baca. During my long career in forensic science, I have been able to take an active part in contributing to the development of forensic science in the U.S. That effort would not be possible without the enlightened support of Sheriff Baca and the other executives in the Sheriff ’s Department and County of Los Angeles. I’d like to acknowledge the work of Dr. Jane Homeyer and Sarah Mikolajczyk in developing a companion CD for this book (available from CRC Press). I suspect that their efforts will greatly complement the learning process. Special thanks are in order to my publisher and editor at CRC Press, Becky McEldowney and Erika Dery, respectively, who were exceedingly patient with me while I was completing the manuscript as well as providing help and encouragement in this effort. And, ﬁnally, thanks to my wife, Susan, who enjoys reminding me that behind every man is a great woman. Susan was a continued source of encouragement to complete the seventh edition of this book. Barry A. J. Fisher Los Angeles, California

© 2004 by CRC Press LLC

The Author

Barry A. J. Fisher grew up in New York City. He received a Bachelor of Science degree in chemistry from the City College of City University of New York in 1966, followed in 1969 by a Master of Science degree in organic chemistry from Purdue University. He also holds an M.B.A. degree from California State University, Northridge, which was awarded in 1973. In 1969, Fisher joined the Los Angeles County Sheriff ’s Department Crime Laboratory. He worked in most of the sections of the laboratory and supervised the Trace Evidence and Toxicology Sections. In 1987, he was appointed Crime Laboratory Director. This crime laboratory is one of the largest municipal laboratories in the U.S. A staff of over 200 people is involved in crime scene investigations, ﬁngerprint identiﬁcation, photography, polygraph, questioned documents, ﬁrearms, toxicology, narcotics analysis, forensic biology, forensic DNA testing, and trace evidence examination. Cases run from straightforward blood alcohol tests to complex serial murder investigations, as well as every other imaginable type in between, and employee drug testing. The laboratory routinely processes thousands of criminal cases each year and is accredited by the American Society of Crime Laboratory Directors/Laboratory Accreditation Board. The laboratory is located near downtown Los Angeles and also operates three regional laboratories in West Covina, Lynwood, and Lancaster. Crime lab services are provided to all law enforcement agencies in Los Angeles County. Fisher has been working with the Sheriff ’s Department, the Los Angeles Police Department, the California Department of Justice, and California State University, Los Angeles, to build a state of the art working–teaching forensic science laboratory on the California State Los Angeles campus. Fisher is a member of several professional organizations. He is a past president of the American Society of Crime Laboratory Directors and a past chairman of the American Society of Crime Laboratory Directors/Laboratory Accreditation Board. He is a Distinguished Fellow and past president of the American Academy of Forensic Sciences. He is past president of the International Association of Forensic Sciences and hosted the 15th triennial meeting of the IAFS on the campus of UCLA in 1999. He serves on the Board of Directors of the National Forensic Science Technology Center, which provides continuing education in forensic science nationwide, and represents the American Academy of Forensic Sciences in the Consortium of Forensic Science Organizations. He has served on a variety of committees including the NIJ-sponsored Technical Working Group on Forensic Science Education and Training (TWGED), the AAFS Forensic Education Programs Accreditation Committee (FEPAC), and the American Bar Association, Criminal Justice Section’s Ad Hoc Innocence Committee to Ensure the Integrity of the Criminal Process. Fisher’s textbook, Techniques of Crime Scene Investigation, is in its seventh edition and enjoys wide popularity. An international speaker, he has lectured in Canada, England, Australia, Singapore, France, Israel, Japan, and the People’s Republic of China on forensic

© 2004 by CRC Press LLC

science laboratory management practices, quality assurance, and related forensic science topics. He is also a part-time lecturer at UCLA Extension in the Department of the Sciences and the Department of the Arts, Writer’s Program. Fisher and his wife Susan live in a suburb of Los Angeles. If you wish to contact the author, you may e-mail him at bajﬁ[email protected].

© 2004 by CRC Press LLC

“We have learned the lesson of history, ancient and modern, that a system of criminal law enforcement which comes to depend on the ‘confession’ will, in the long run, be less reliable and more subject to abuses than a system which depends on extrinsic evidence independently secured through skillful investigation.” Escobedo v. Illinois, 378 U.S. 478, 488–489 (1964)

© 2004 by CRC Press LLC

Prologue

September 11, 2001, marked an entirely new set of issues for forensic investigators to consider. Beyond the traditional tasks forensic scientists must perform during criminal investigations, they now have a set of added concerns. Since September 11, ﬁrst responders and laboratory personnel have been called on to identify victims in mass casualties, as was the case in New York City, the Pentagon and in the ﬁelds of western Pennsylvania. Investigators have been required to handle anthrax-tainted physical evidence and are wary about future possibilities of contaminated evidence. One of the newer terms in the aftermath of 9/11 is bioforensics — determining the source of diseases in terrorist acts. Another term new to forensic science is WMD — weapons of mass destruction. These may consist of chemical, biological, nuclear and radiological materials that become part of crime scenes and the evidence associated with crime scenes. Forensic practitioners will need to be knowledgeable about all sorts of new areas in the public health, terrorist and military realms that they have never had occasion to think about before. In the post September 11 world a fair question for state and local forensic practitioners is, “What is our appropriate role in supporting the investigation of the terrorist incident?” The investigation of domestic terrorist acts is clearly a federal responsibility with the FBI designated as the lead agency. However, it is unrealistic to expect the FBI, the Department of Homeland Security, FEMA, Department of Defense, and others to be at the scene immediately, especially if multiple events occur. More likely, ﬁrst responders will be made up of local police, ﬁre, rescue, crime scene technicians, medical examiner personnel and forensic scientists. If several incidents occur simultaneously around the country, local ﬁrst responders would be expected to handle the scene and the aftermath until federal assistance became available. Not all the activities surrounding a terrorist attack are the responsibility of federal agencies such as the FBI. Some functions are clearly in the hands of the local authorities, such as the identiﬁcation of mass civilian casualties. In the World Trade Center attacks, the New York City Ofﬁce of the Chief Medical Examiner had the job of identifying the victims. Although other public and private resources will provide important assistance, the local medical examiner’s ofﬁce or the coroner has the primary responsibly to identify the dead. The problem is that few if any plans to deal with terrorist events consider a role for local and state forensic science resources. Terrorism is one of many issues that forensic science practitioners and administrators must consider in the years to come; all of these issues can be viewed as part of a greater issue of a lack of planning. Stated simply, there is a critical need to develop a national forensic science strategy. Stakeholders who are part of the forensic science delivery system and users of forensic science services need to be brought together to consider all issues thoughtfully. Some are focused solely on forensic DNA testing, but the issues are much greater.

© 2004 by CRC Press LLC

The federal government recently called for the creation of a National Forensic Science Commission to study rapidly evolving advances in all areas of the forensic sciences and to make recommendations to maximize the use of the forensic sciences in the criminal justice system.1 Such a commission could study the following areas, among others: •

•

•

What is the value of forensic science applied to the criminal justice system? There are currently no quantitative measures (other than anecdotal reports) to demonstrate the worth of investing in forensic science. If quantitative information can be developed to show that a small investment in forensic science results in signiﬁcant value added to the overall effort of police and prosecutors, funding for forensic science should be easier to achieve. Similarly, no information is available to demonstrate the social value of forensic science to crime victims and their families. It would not be surprising to ﬁnd that victims and their families are strongly supportive of public forensic science. These advocates could be marshaled as a force to secure more needed resources for forensic sciences. One only needs to consider the popularity of TV shows like CSI and a host of reality-based shows as an indicator of the public’s interest in and potential support for forensic science. How will future forensic science stafﬁng needs be met? It will be necessary to ﬁll potentially thousands of forensic science positions due to retirements and a projected demand for more services. During the 1970s, Law Enforcement Assistance Administration (LEAA) funding resulted in the growth of forensic science labs and staffs around the U.S. Those persons hired at that time are now at the ends of their careers. In addition, the demand for DNA testing is likely to press the need for more forensic scientists in the future. As many as 10,000 new practitioners have been suggested in the next 5 to 10 years. How are we to educate, recruit and train this large number of new personnel? In addition, labs are looking for more forensic scientists at the M.S. and Ph.D. levels. For universities to run graduate level programs in the sciences, research dollars must be made available. However, the amount of research and development funds available to support forensic science at the National Institute of Justice is small and all but nonexistent from the National Science Foundation, and other funding sources. Science and law issues should be considered. Case law (Daubert2 etc.) and the Federal Rules of Evidence (rule 7023) are being used by defense attorneys in criminal cases in an attempt to challenge the reliability of “pattern evidence,” i.e., ﬁngerprints, handwriting, footwear evidence, bite marks, etc. Courts are allowing these challenges because of changes in their views of science. Prior to Daubert, in order to be admissible, scientiﬁc evidence had to meet the Frye general acceptance standard. With changes in case law and the Federal Rules of Evidence, some defense attorneys have seized on the reliability issue to try to exclude certain classes of evidence. Although these attacks have generally been unsuccessful, it is reasonable

1 March 11, 2003, U.S. Department of Justice Fact Sheet, The President’s Initiative to Advance Justice through DNA Technology. 2 Daubert v. Merrell Dow Pharmaceuticals, 113 S. Ct. 2786 (1993). 3 “If scientiﬁc, technical, or other specialized knowledge will assist the trier of fact to understand the evidence or to determine a fact in issue, a witness qualiﬁed as an expert by knowledge, skill, experience, training, or education, may testify thereto in the form of an opinion or otherwise, if (1) the testimony is based upon sufﬁcient facts or data, (2) the testimony is the product of reliable principles and methods, and (3) the witness has applied the principles and methods reliably to the facts of the case.”

© 2004 by CRC Press LLC

•

•

•

to expect the challenges to continue. The National Academies are considering a study of ﬁngerprints, which if funded, may answer the reliability challenge much in the same way that DNA was deemed reliable after two National Research Council Reports. What do public forensic science laboratories need? An assessment of the needs of public forensic science institutions is necessary to help provide adequate resources to assist crime labs and medical examiner ofﬁces in providing quality and timely forensic science services to the criminal justice system. For example, can standards for the number of forensic scientists per 100,000 police ofﬁcers be developed? Can standards for evidence turn-around times be established? What are reasonable amounts of continuing education training to require of forensic scientists? What is the federal government’s role in developing solutions to these concerns? What is the role of public forensic science labs at the state and federal level in the event of a terrorist attack? As stated earlier, roles for state and local forensic science laboratories in the event of terrorist act have yet to be deﬁned. Once a role is deﬁned, will state and local forensic labs be ready to deliver the necessary services? The appropriate stakeholders must be brought together to consider this challenge. Is collaboration between state and local forensic science and federal forensic science laboratories sufﬁcient? Federal forensic science labs play a vital role in the administration of justice and provide important support to state and local forensic science laboratories. However, a greater degree of collaboration between federal and state/local forensic science labs is desirable. Interaction between local and federal practitioners and lab administrators is important to allow all points of view to be considered and to make the best use of public tax monies.

The establishment of a national forensic science commission would have the desired effect of considering these and other critical issues with the desired outcome to develop well-considered public policy along with adequate funding. The justice system and the public at large are the beneﬁciaries of such a program. Forensic science is more than just applied science. During the O. J. Simpson trial, colleagues called to tell me that the Simpson defense team, in order to raise questions about the crime scene procedures, was using an earlier edition of this textbook. I learned a powerful lesson from this case: there is much more to crime scene investigation than simply proper police investigative techniques and forensic scientiﬁc and technical skill. Appearance and perception as well as the ability to communicate effectively to a jury are equally important. “It’s not only important to be sharp; you have to look sharp, as well!” That advice was given by an FBI instructor at a crime scene class I attended many years ago. To put it another way, appearances and perception are every bit as important as knowledge, skills, and ability, at least in the eyes of the jury and the public. It would be naive for anyone planning a career in police work, forensic identiﬁcation, or forensic science to underestimate the importance of the role of the expert witness in the courtroom. An investigator with the cleverness of Sherlock Holmes or a forensic scientist with the wisdom and understanding of Albert Einstein would be ineffective in a criminal investigation if he or she were unable to convince a jury made up of lay people. Verbal communication skills are every bit as important as technical expertise in being a successful expert witness.

© 2004 by CRC Press LLC

Professional ethics are also crucial. At one time, it would have been extraordinary to discuss integrity and ethics in a textbook on crime scene investigation. First, I apologize to the vast majority of practitioners who do not require any reminder. These professionals know that there is only one way to conduct their professional (and, hopefully, personal) lives — with honesty and integrity. However, in a small number of instances, ethical failings among practitioners make restating some fundamental principles necessary. Criminal justice practitioners should know how to behave and what actions are right and honorable. For whatever reasons, notions of ethics, duty, and honor are ideals that have been forgotten by some. A discussion on the subject is in order because forensic practitioners and police investigators occasionally forget their public duty. In addition, those new to the profession must be told what their role in the criminal justice system is in clear, unmistakable terms. A colleague once explained ethical conduct by using a simple statement: There is no way to make a wrong thing right! In a forensic context several examples of dishonorable conduct come to mind. The following situations, unfortunately, refer to actual incidents: • • • • • • • • • • •

Planting evidence at a crime scene to point to a defendant Collecting evidence without a warrant by claiming exigent circumstances Falsifying laboratory examinations to enhance the prosecution’s case Ignoring evidence at a crime scene that might exonerate a suspect or be a mitigating factor Reporting on forensic tests not actually done out of a misguided belief that the tests are unnecessary Fabricating scientiﬁc opinions based on invalid interpretations of tests or evidence to assist the prosecution Examining physical evidence when not qualiﬁed to do so Extending expertise beyond one’s knowledge Using unproved methodologies Overstating an expert opinion by using “terms of art” unfamiliar to juries Failing to report a colleague, superior, or subordinate who engages in any of the previously listed activities to the proper authorities

This list of wrongdoings can be categorized in several ways. Some failings are actually criminal in nature; they are felonies that could result in prison terms for the perpetrator. Others represent negligent conduct and could result in civil litigation against the expert, a superior, or the agency. Yet another class of failings constitutes unethical conduct that could result in censure, suspension, or expulsion from professional organizations. Occasionally, situations arise that contain an element of ambiguity. How might one determine the best course of action? Although the answer may not be clear in every case, one method is to ask the following questions: • •

Would I be proud to tell my children or my parents what I did? How would my actions look on the front page of the morning newspaper?

If it remains uncertain whether actions are inappropriate or improper, seek the advice of a trusted professional colleague. Every forensic discipline has members who serve as pillars of the profession; seek out those persons and ask for guidance. © 2004 by CRC Press LLC

Those of us who work for public agencies and who investigate criminal acts carry a difﬁcult burden. The consequences of our conduct are considerable. Defendants convicted of capital crimes may face the death penalty or long years of conﬁnement, in part from the physical evidence we collect and about which we provide expert testimony. It is troubling to think that those responsible for committing a criminal act may be set free because of actions committed or omitted by a forensic investigator. Indeed, few professions carry this amount of responsibility or hold such public trust as do forensic scientists and crime scene investigators. Earlier, I mentioned the Simpson case. The criminal justice system and forensic science were also on trial. Many condemned the trial as a media circus because of the television courtroom coverage. Some believe that Mr. Simpson should have been convicted of the murders while others proclaimed that justice was done. In fact, the jury listened to the evidence and made its decision: The People failed to prove their case beyond a reasonable doubt to the jury’s satisfaction. Mr. Simpson’s defense team used an earlier edition of this book to argue how physical evidence should have been handled and the proper techniques for conducting a crime scene investigation when they cross-examined the prosecution criminalists. There are few immutable rules in crime scene investigations. A notion I try to stress in this book is that a set of guidelines based on common sense can be applied to most crime scenes; however, guidelines cannot always be followed. Any experienced crime scene investigator knows that packaging wet, bloody evidence in plastic should be avoided. Wet biological evidence packaged in this manner will deteriorate much more quickly than air-dried evidence. Faced with blood-soaked clothing or bedding, however, separate packaging in a clean plastic trash bag for immediate transportation to the forensic science laboratory is an appropriate way to handle such items if there is no way to dry the items at the scene. Situations differ and it is important to be ﬂexible. As humans, we are subject to mistakes. It is impossible to handle every investigation without making some mistakes. At best, we can try to make as few errors as possible and to learn from past errors. Some people have a compelling urge to be “Monday-morning quarterbacks.” Many of us would be wealthy indeed if we could receive a dollar for each time we have said, “If only I had collected that item of evidence,” or “I should have done thus and so, a different way,” or “Why didn’t I think of that at the time; it seems so obvious now.” The adage that “hindsight is always 20–20” is a fact of life with which we must live. The Simpson case shifted to a degree the focus of forensic science from the laboratory to the crime scene. The crime scene investigation process now takes on a more important role than before. Defense attorneys have learned that if they are able to show that the initial handling of the physical evidence at the crime scene was faulty, then the evidence can be kept out of the trial, or at least tarnished in the eyes of the jury. Training and continuing education for uniformed ofﬁcers, detectives, crime scene investigators, and forensic scientists, especially in the proper collection and preservation of physical evidence at crime scenes, is extremely important. Training in the technical areas and in how to be a better expert witness needs to be stressed. Written evidence-gathering procedures must also be reevaluated and, if necessary, rewritten. All law enforcement personnel involved in the investigation must follow their agency’s policies and physical evidence procedures. The reasons for this are evident. Defense attorneys will attempt to show the written policies and procedures were not followed or, if policies and procedures do not exist, that the practices employed were not © 2004 by CRC Press LLC

generally acceptable or personnel lacked appropriate training. The results are the same: even if forensic tests point to the defendant, improper or inadequate evidence collection and preservation techniques will render the evidence inadmissible or its value will be diminished. A better-informed defense bar will also raise questions about the quality of forensic science laboratories and their forensic practitioners. One way to evaluate a laboratory’s quality is to inquire if it is accredited. In the U.S. and several foreign countries, that means American Society of Crime Laboratory Directors — Laboratory Accreditation Board (or ASCLD/LAB)4 accreditation. Other programs have been developed that follow the ISO 17025 standards5 as well. In fact, with the number of public forensic laboratories that have already become accredited, it is only a matter of time before accreditation will be a de facto requirement for evidence admissibility. No one is likely to undergo surgery in a nonaccredited hospital; similarly, courts, prosecuting and defense attorneys, the police, and the public should demand that their laboratories meet basic forensic science laboratory accreditation standards such as those articulated in ASCLD/LAB accreditation criteria. Just as a forensic science user should expect a laboratory to be accredited, a similar question may be asked of the forensic science practitioner: is he or she board certiﬁed? There are a number of professional accrediting bodies. In the criminalistics arena, it is the American Board of Criminalistics.5 The International Association for Identiﬁcation6 offers an exemplary certiﬁcation program in ﬁngerprint identiﬁcation and crime scene investigation. There are also other forensic science and medical certifying bodies in areas such as questioned documents, toxicology, dentistry, pathology, anthropology, and psychiatry that help to identify competent practitioners. Certiﬁcation of forensic scientists: 1) measures quality, 2) enhances credibility, 3) introduces a degree of peer standardization, and 4) enhances consumer conﬁdence. However, not all certifying programs are to be trusted. Persons considering a board certifying program are encouraged to evaluate them critically. A program that does little more than require the payment of a fee should raise questions. Caveat emptor! Continuing education and attendance at professional association seminars and workshops are essential to professional competency and professional development. To demonstrate this point, ask, “Would I consider going to a physician, dentist, accountant, lawyer, or other professional who does not periodically attend continuing education classes to keep up his or her professional competency?” Funds for professional development should be considered a priority in all law enforcement organizations that operate forensic science laboratories and ﬁngerprint identiﬁcation laboratories. 7 Just as continuing education and training are important, so is ongoing competency or proﬁciency testing for forensic scientists and forensic science laboratories. There are a variety of proﬁciency testing modalities that demonstrate mastery of technical procedures. Proﬁciency testing need not be double blind. Proﬁciency testing can be: blind, declared, reanalysis, interlaboratory, or “round robin.” Proﬁciency test results are public records and 4

http://www.ascld-lab.org/ http://www.criminalistics.com/abc/A.php 6 http://www.theiai.org/certiﬁcations/ 7 An agency should plan on budgeting about $1,500 per examiner per year for continuing education and training if it hopes to operate a quality forensic science or identiﬁcation laboratory (NIJ Technical Working Group on Education and Training in Forensic Science). 5

© 2004 by CRC Press LLC

can be subpoenaed to demonstrate how well laboratories and practitioners perform in such tests. Forensic science funding needs are often ignored until some horriﬁc revelation brings them notice. Often inadequate funding goes along with inadequate oversight from the local criminal justice establishment. Quality and timely work have a price tag and inadequate funding has consequences. Parent organizations must remember to fund staff and support operations in addition to line units. Failure to provide adequate funding to ensure quality work and timely lab service is unconscionable. The damage done when failures in the forensic science delivery system occur can be appalling. The citizens of a democracy have a right to expect that justice be administered fairly and impartially. Should that expectation be any different for an essential element of public safety — forensic science?

© 2004 by CRC Press LLC

Table of Contents

Foreword Preface Acknowledgments The Author Prologue

1

Introduction Identification and Individualization of Physical Evidence Collection and Preservation of Physical Evidence Important Considerations in Crime Scene Investigations Guidelines for Forensic Laboratory Management Practices Expert Witness Tips Before Going to Court Giving Expert Testimony Cross Examination Other Points Teamwork Professional Development

2

First Ofﬁcer at the Crime Scene The First Officer at the Scene Recording the Time Entering the Scene Proper Protecting the Integrity of the Scene Injured Person on the Scene Dead Person on the Scene Summoning the Coroner Firearms and Ammunition on the Scene When a Suspect Is Found at the Scene What to Do Until Investigating Personnel Arrive Continued Protection of the Scene

3

The Crime Scene Investigator Actual Examination of the Scene

© 2004 by CRC Press LLC

4

Specialized Personnel at the Crime Scene Health and Safety Issues at Crime Scenes Chemical or Biological Terrorist Crime Scenes Indicators of a Possible Biological Terrorist Threat Indicators of a Possible Chemical Terrorist Threat Health and Safety Considerations for Crime Scene Personnel Conclusion

5

Processing the Crime Scene Plan of Action Note Taking Crime Scene Search Crime Scene Photography Types of Cameras Admissibility of Photographs Videotape Sketching the Crime Scene Information Included in Crime Scene Sketches Equipment Types of Sketches Locating Objects in the Sketch Computer Programs Admissibility of Sketches Collection of Evidence

6

Establishing Identity Fingerprints and Palm Prints How Do Fingerprints Occur? Where to Look for Fingerprints Different Types of Fingerprints Fingerprint Developing Techniques Development with Powders Lasers and Alternative Light Sources Image Processing Automated Fingerprint Identification Systems Preservation of Fingerprints How Long Does a Fingerprint Remain on an Object? The Effect of Temperature Conditions on the Possibility of Developing Fingerprints Examination of Developed Fingerprints Palm Prints Packing Objects on which Prints are Found Taking Fingerprints for Elimination Prints of Other Coverings Handwriting Examination Identification of Human Remains Taking Fingerprints Photographing

© 2004 by CRC Press LLC

Marks of Trades or Occupations Making a Description The Deceased’s Clothing Laundry Marks Watchmaker’s Marks Jewelry Eyeglasses Teeth Facial Reconstruction Determination of Gender Determination of Age Length of Body Hair Color Blood Type Identification in Mass Disasters

7

Trace Evidence and Miscellaneous Material Sources of Trace Evidence Clothing Footwear Evidence from the Body Trace Metal Detection Other Objects as Sources of Trace Evidence Collection and Preservation of Trace Evidence Examples of Trace Evidence Building Materials Asbestos Safe Insulation Paint Rust Metals Textiles and Fibers Buttons Cordage and Rope Cigarettes and Tobacco Matches Burned Paper Ash Soil Wood Plant Material Glass Objects Left at the Crime Scene Paper Articles of Clothing Product Markings Foodstuffs Cosmetics Hair Feathers

© 2004 by CRC Press LLC

Electrical Wire Broken Tools Tape Headlamps Computer Seizure Collecting Videotape Evidence Determine if There Is a Videotape Stop the Recorder Confiscate the Tapes Immediately, Taking the Usual Chain-of-Evidence Steps Document the Video System’s Physical Relationship to the Crime Scene Seek Technical Assistance if Problems Occur Other Trace Evidence

8

Blood and Other Biological Evidence A Word of Caution! Universal Precautions Bloodstain Pattern Recognition Presumptive Tests for Blood Searching for Bloodstains Description and Recording of Bloodstains Collection and Preservation of Bloodstains Removal of Bloodstains Bloodstained Objects Blood Typing Collection of Known Specimens Forensic DNA Typing RFLP-Based Technology PCR-Based Technology Mitochondrial DNA CODIS Forensic DNA and Unsolved Cases SWGDAM The Future

9

Impression Evidence Footprints The Value of Footprints Preservation of Footwear and Tire Impressions Footprints on Floors Preservation of Footwear Evidence Photographing Footwear Impressions Casting with Dental Stone Casting Water-Filled Impressions Casting Impressions in Snow Preservation of Footprints (Dust Prints) Taking Comparison Footprints from a Suspect Comparison of Footprints Marks on Clothes and Parts of the Body Fabric Marks

© 2004 by CRC Press LLC

Tooth Marks The Preservation of Bite Marks Casting Material for Bite Mark Evidence Human Skin Foods Tool Marks Preservation of Tool Marks Casting Tool Marks Trace Evidence on Tools Preserving a Tool Fragments of Tools Typed Documents

10

Firearms Examination Characteristics of Firearms Ammunition Firearms Evidence Gunshot Residue Analysis Collecting Firearms Evidence Handling of Firearms Cartridge Cases Bullets Marking Bullets Small Shot Test Firing Powder Pattern Examination National Integrated Ballistic Information Network (NIBIN)

11

Arson and Explosives Physical Evidence Explosives Low Explosives High Explosives Blasting Agents Military Explosives Homemade Explosives Bomb Scene Investigation

12

Illicit Drugs and Toxicology Psychoactive Drugs Central Nervous System Depressants Central Nervous System Stimulants Hallucinogens Crime Scene Search Searching a Suspect Searching a Dwelling Searching a Vehicle Clandestine Drug Laboratories

© 2004 by CRC Press LLC

Collection and Preservation of Evidence Toxicology U.S. DEA Drug Schedule Classification Schedule I Schedule II Schedule III Schedule IV Schedule V

13

Investigating Sexual Assault and Domestic Abuse Crimes Rape Preliminary Interview Medical Examination Collection of Physical Evidence Date-Rape Drugs Other Sexual and Abusive Assaults Sexual Child Molestation and Incest Homosexual Assault Elder Abuse Conclusion

14

Burglary Investigation Points of Entry Entry through Windows Entry through Doors Entry through Basement Windows and Skylights Entry through Roofs Entry through Walls Entry through Floors Simulated Burglaries Detailed Examination of the Scene Safe Burglaries Safe Burglaries Using Explosives

15

Motor Vehicle Investigation Vehicle Theft Abandoned Vehicles Homicide in a Vehicle Hit-and-Run Investigation Marks from Vehicles Wheel Marks Skid Marks

© 2004 by CRC Press LLC

16

Homicide Investigation Murder, Suicide, or Accident? Cause of Death Suicide Signs of Struggle Location of Weapon Examination of a Dead Body at the Crime Scene Murder Detailed Examination of the Scene of the Crime Outdoor Crime Scenes Discovering a Body Hidden at Another Location Investigation of a Greatly Altered Body or Skeleton The Scene of Discovery Outdoors Indoors Packing and Transporting Determining the Number of Individuals Examining Remains of Clothing and Other Objects Clothing Boots and Shoes Other Objects Estimating the Time of Death Postmortem Signs of Death Decomposition of the Body Action of Insects and Other Animals on a Dead Body Other Indications of Time of Death The Autopsy Injuries from External Mechanical Violence Injuries from Sharp External Violence Marks or Damage on Clothing Defense Injuries Firearm Injuries Bullet Injuries Close and Distant Shots Damage to Clothes from Shooting Modes of Death from Shooting Explosion Injuries Death by Suffocation Death from Electric Currents Violent Death in Fires Death by Freezing Death by Poisoning Rape–Homicide and Sexual Assault-Related Murders Infanticide and Child Abuse Trunk Murder, Dismemberment of the Body Serial Murders

© 2004 by CRC Press LLC

Appendix A

Equipment for Crime Scene Investigations

Appendix B

Forensic Science-Related Websites

Appendix C

Terrorism and Domestic Preparedness Websites

Bibliography

© 2004 by CRC Press LLC

Introduction

1

Webster’s Dictionary deﬁnes evidence as something legally submitted to a competent tribunal as a means of ascertaining the truth of any alleged matter of fact under investigation before it. Police investigators deal with evidence on a daily basis. Their ability to recognize, collect, and use evidence in criminal investigations determines to a large degree their success as investigators. Evidence can be divided into two broad types: (1) testimonial evidence and (2) real, or physical, evidence. Testimonial evidence is evidence given in the form of statements made under oath, usually in response to questioning. Physical evidence is any type of evidence with an objective existence, that is, anything with size, shape, and dimension. Physical evidence can take any form. It can be as large as a house or as small as a ﬁber. It can be as ﬂeeting as an odor or as obvious as the scene of an explosion. In fact, the variety of physical evidence that may be encountered in an investigation is inﬁnite. What is the value of physical evidence and why should police investigators concern themselves with an understanding of the uses and ways to collect physical evidence? Physical evidence can prove a crime has been committed or establish key elements of a crime. Case. Proof of rape requires showing nonconsensual sexual intercourse. In an alleged rape case, the victim’s torn clothing and bruises were sufﬁcient to prove nonconsent. Case. Arson investigators dispatched to the scene of a suspicious ﬁre collected some burned carpeting. Later analysis proved that gasoline was present in the carpet, proving that the ﬁre was intentionally started and, therefore, arson. Physical evidence can place the suspect in contact with the victim or with the crime scene. Case. A suspect was apprehended shortly after an alleged rape in the victim’s home. Cat hair was found on the lower portion of the suspect’s trousers, which the suspect was at a loss to explain. The victim owned two cats.

© 2004 by CRC Press LLC

Figure 1.1 In order for a defendant to be charged with possession of a controlled substance, the forensic science laboratory must establish that the seized evidence is listed in the code. Labels on pharmaceuticals sometimes describe one drug when in fact the container holds another. In this case, some of the steroids were tested and found to be different steroids from those listed as the contents. (Los Angeles County Sheriff’s Department.)

Physical evidence can establish the identity of persons associated with the crime. Case. Every safe burglar knows not to leave ﬁngerprints at the crime scene, so it was not surprising to ﬁnd at the scene latex surgical gloves that were used on the safe. The identity of the burglar was established by developing ﬁngerprints inside the rubber gloves. Case. DNA typing proved that a lone defendant was responsible for a series of rape cases in a major metropolitan area. Physical evidence can exonerate the innocent. Case. An 8- and 9-year-old brother and sister accused an elderly neighbor of child molestation. They claimed that the man gave each of them pills that made them feel drowsy and then he molested them. The investigator had a physician examine the children and blood and urine specimens were collected for a toxicology screen. The analyses of the blood and urine specimens were negative. When presented with this information, the children confessed that they had fabricated the entire story because they disliked their neighbor. Physical evidence can corroborate the victim’s testimony. Case. A motorist picked up a female hitchhiker. She claimed that he pulled a knife and attempted to rape her. During the struggle, the woman’s thumb was cut before she managed to escape. She related her story to the police and the suspect was eventually arrested. During the interrogation, the suspect steadfastly proclaimed his innocence. The investigator noted a small quantity of dried blood on the suspect’s left jacket lapel. He claimed the blood came from a shaving mishap. The investigator submitted the jacket along with blood samples from the suspect and the victim to the crime laboratory. The results indicated that the blood on the jacket could not have come from the suspect, but came from the victim. The physical evidence was instrumental in obtaining a conviction for attempted rape.

© 2004 by CRC Press LLC

Figure 1.2 Example of a physical match. A comb (A) with three missing teeth was found in the suspect’s possession. Two plastic teeth (B) found at the crime scene were ﬁtted to the comb (C). The evidence placed the victim at a burglary. (Los Angeles County Sheriff’s Department.)

A suspect confronted with physical evidence may make admissions or even confess. Case. Cattle rustling still occurs from time to time. Blood found on a suspect’s shirt was tested and determined to be bovine, that is, from a cow. The suspect, who ﬁrst claimed the blood was his own, made a full admission when confronted by the evidence. Physical evidence may be more reliable than eyewitnesses to crimes. Psychological experiments have shown that observations made by test subjects in simulated violent crimes are inaccurate over a period of time after the event. Study. Volunteers in a psychological test were witnesses to staged assaults. At the conclusion of the mock crimes, they were asked to detail their observations in writing. Over a period of several months, they repeatedly were asked to write down what they had observed. The study showed that people ﬁll in gaps to events not observed. If a portion of an event was not seen or did not make sense, the subjects made up scenarios that seemed reasonable to the episode. This behavior occurred subconsciously; subjects were not aware that it was taking place. They simply reported what they believed they had seen.

© 2004 by CRC Press LLC

Figure 1.3 (A color version of this ﬁgure follows page 256.) The order of clothing fragments caught in the hollow-point round ﬁred by a deputy sheriff helped to reconstruct the sequence of events in an ofﬁcer-involved shooting. An innocent bystander and an armed robber were killed by the shot and it was up to the lab to determine who was struck ﬁrst. The order of the fragments of clothing proved that the bullet ﬁrst hit the robber and then the bystander. (Los Angeles County Sheriff’s Department.)

Court decisions have made physical evidence more important. The U.S. Supreme Court, in a number of decisions such as Miranda, has limited the authority of the police to rely on statements and confessions made by defendants. These landmark cases have, in effect, shifted the attention in proving cases to physical evidence. Juries in criminal cases expect physical evidence. Two unrelated factors have biased the public’s notion of the role of physical evidence in criminal cases. Jurors expect physical evidence in a trial; after all, that is the way it is on television shows such as CSI: Crime Scene Investigation, Court TV and other programs. Science and technology are perceived by the public to be unbiased and not subject to manipulation. If scientiﬁc testing is used to evaluate and characterize physical evidence, the public is more inclined to believe that the police investigation was properly conducted. Negative evidence — the absence of physical evidence may provide useful information and even stop defense arguments at the time of trial. Case. In an insurance fraud, the victim claimed his home was burglarized. No evidence of forced entry could be found and eventually the fraud was discovered.

© 2004 by CRC Press LLC

Figure 1.4 The victim in this case was raped and strangled in her home in a suburb of Beijing. The criminal tried to disguise the crime scene by tying a lamp cord from a desk lamp around the victim’s neck and making the death appear to be a suicide. A latent ﬁngerprint was discovered on the base of the lamp using super glue. The case was solved when the latent print was matched to a neighborhood youth who had claimed never to have been in the victim’s house. (Institute of Forensic Science, Beijing, China.)

Identiﬁcation and Individualization of Physical Evidence Some investigators may think that every item of physical evidence can be directly associated to a speciﬁc person, place, or thing and believe that it is possible for a single strand of hair or a ﬁber to be linked to a unique source. This is not generally the case. Although some types of physical evidence may come from one and only one source, most physical evidence may only be associated with a class or group. Only a few kinds of physical evidence can be individualized. Individualization means that an item of evidence comes from a unique source. It can be shown to be directly associated with a speciﬁc individual source. A broken piece of plastic physically ﬁtted to reconstruct an item is an example of individualization. Other types of evidence including ﬁngerprints, tool marks and ﬁred bullets are examples of evidence that may be associated with a unique source (Figure 1.5). The majority of physical evidence found at crime scenes can only be identiﬁed. Identiﬁcation means that the items share a common source. The items can be classiﬁed or placed into groups with all other items having the same properties. The difference between individualization and identiﬁcation can be a subtle one. Consider the following example: a blue-colored cotton ﬁber is found at the scene of a burglary. A suspect wearing a torn blue cotton shirt is apprehended. All the tests conducted at the crime laboratory on the evidence ﬁber and exemplar ﬁbers from the shirt show them to

© 2004 by CRC Press LLC

Figure 1.5 Physical matches are another example of individual characteristics. The tiny paint chip in the evidence container on the left inset was removed from the suspect’s wrench and a physical match was made to an area on the bolt (bottom right inset) from a safe. The photograph shows a close-up of the physical match. (Illinois State Police.)

be identical. Can it be concluded that the blue cotton ﬁber found at the scene deﬁnitely came from the torn blue cotton shirt worn by the suspect? (See Figure 1.6.) No! The best that can be stated from this information is that the ﬁber could have come from the shirt in question or any other one manufactured with similar blue cotton ﬁbers. The item has been identiﬁed as a blue cotton ﬁber and can be placed into a class of all other similar blue cotton ﬁbers. No matter how much testing is done on that evidence, the conclusion will always be the same. Contrast the ﬁber with a ﬁngerprint. The ﬁngerprint may be identiﬁed. It can be placed into a group, e.g., a whorl or loop. In addition, ﬁngerprint evidence can go well beyond identiﬁcation; ﬁngerprints can be shown to be unique. An examination can show that the latent print comes from only one person and no other. The print has been individualized. Most physical evidence cannot deﬁnitely connect a suspect to a crime as ﬁngerprint evidence can. This should not diminish the usefulness of that evidence. Physical evidence that is identiﬁed can corroborate testimony, place a subject at a scene, and be useful in a variety of ways as an interrogation tool (Figure 1.7).

© 2004 by CRC Press LLC

Figure 1.6 Class characteristics place an item of evidence in a speciﬁc class or group. The upper two strap segments in the photograph were found in a murder suspect’s van. The lower strap is of similar manufacture, design, and material content. It was from a similarly designed and manufactured swimsuit reported to have been worn by the victim. This is an example of class characteristics. (Los Angeles County Sheriff’s Department.)

Case During a robbery of a Ventura cocktail lounge, a lone gunman tied the manager hand and foot with lengths of white plastic clothesline. Later, another robbery occurred at a cocktail lounge approximately 20 miles north of Ventura, during which the manager was bound with white plastic clothesline in the same fashion. This time, however, the victim was shot and killed by a single .45-caliber bullet ﬁred into the back of his head. An intensive investigation led to a suspect, a middle-aged part-time cook who resided in Van Nuys, immediately northwest of Los Angeles. A search of his car led to the discovery of a 24-foot length of white plastic clothesline in the car trunk and two lengths of clothesline, each about 40 inches long, under the driver’s seat. Laboratory examinations conducted by the Ventura County (California) Sheriff ’s Department crime laboratory disclosed that the sections of clothesline from the three sources all bore the same class characteristics, including the physical and chemical composition of the plastic components. The components consisted of 121 interior ﬁlaments of nine different plastic types and one metallic ﬁlament, all

© 2004 by CRC Press LLC

Figure 1.7 These items provide an unusual example of class characteristics. The body of a hit-and-run victim was found next to a major highway. A suspect vehicle was located with an unusual impression (A) that matched the pedestrian’s wristwatch band (B). (Division of Identiﬁcation and Forensic Science, Israel National Police.)

contained in a white plastic cover. The outer covers or sheaths were approximately one-quarter inch in diameter. Examination of the interior portion of the sheaths showed that the perimeter ﬁlaments left their impressions permanently in the interior of the sheaths as a result of the manufacturing process. In this process the

© 2004 by CRC Press LLC

Figure 1.8 Sometimes class characteristics may be unusual enough to permit the inference that an item of evidence came from a single source. This illustration shows a plaster cast (left) taken from a burglary scene and the suspect’s shoe (right). (The photographic negative was ﬂipped in order to show the cast in reverse orientation so that the two items can be more easily examined.) The tread on the sole and that on the plaster cast have the same design and similar wear patterns. The staple in the sole, also found in the cast, is convincing evidence that this shoe made the impression. (Los Angeles County Sheriff’s Department.)

ﬁlaments constituting the core are pulled through white PVC melt and extruded to produce the white outer cover (Figure 1.9). Experiments showed that successive cross-section cuts along a single clothesline section, one-quarter inch apart, resulted in noticeable differences because the ﬁlaments vary in position from point to point along the clothesline. By virtue of this strong individual characteristic, these ﬁlament impressions constituted the strongest single feature of identiﬁcation. As a result, the Ventura robbery was conclusively tied to the suspect. On the other hand, the robbery/murder case was not connected conclusively through the clotheslines. No matching ends were present to tie this case with the ﬁrst robbery or the car. Measurements of all the clothesline sections, collectively, indicated that less than one complete clothesline was present. A shortage of about 10 feet existed. For all that is known, a portion or parts of it may be lying on a police property room shelf somewhere perhaps to link another crime. In any event, the accused person was convicted of robbery and murder, based on the plastic clothesline and other physical evidence.

© 2004 by CRC Press LLC

Figure 1.9 Cross-sections of the clothesline, showing similarities. (Ventura County Sheriff’s Department, Ventura, California.)

Collection and Preservation of Physical Evidence The major theme of this text concerns the proper handling of physical evidence. Two of the main areas that must be considered in any discussion of the proper techniques of collection and preservation of physical evidence are the legal and scientiﬁc issues concerning collection and preservation of physical evidence. Although laws regarding physical evidence vary from state to state, they have many similarities. Before any evidence is seized, the need for a search warrant or court order should be considered. Case law is constantly changing, so investigators should keep abreast of the latest developments. Depending on circumstances, court orders may be required for searching the crime scene and collecting evidence, such as blood samples, hair specimens, medical tests, and teeth impressions, from a suspect. The prosecutor’s ofﬁce should be consulted if there is any doubt. Failure to secure a search warrant may result in severe legal sanctions by the court. In some cases, the physical evidence seized at a crime scene may be inadmissible in court for lack of a warrant. In fact, a legal doctrine called fruit of the poison tree provides that any subsequent information derived from illegally seized physical evidence is inadmissible in court and cannot be used. Stated simply: if unsure of the situation, consult with the prosecutor’s ofﬁce. Mistakes in this area can be costly and cases have been lost for lack of search warrants or court orders to seize evidence. The concept of a “chain of custody” or “chain of evidence” is important to understand. A court will require proof that evidence collected during an investigation and the evidence ultimately submitted to the court are one and the same. To prove that the integrity of the

© 2004 by CRC Press LLC

physical evidence has been maintained, a chain of custody must be demonstrated. This chain shows who had contact with the evidence, at what time, under what circumstances, and what changes, if any, were made to the evidence. Typically, evidence is put into a container with a label or tagged. Identifying information pertaining to the case is written on the container or tag as well as in reports and logs to establish the chain. Police department policy may dictate which information is required, but usually the following types of information are needed to establish the chain of custody: • • • • •

Name or initials of the individual collecting the evidence and each person subsequently having custody of it Dates the item was collected and transferred Agency, case number, and type of crime Victim’s or suspect’s name Brief description of the item

This information serves to prove the chain of custody to the court and assists in admitting the items into evidence. Storage of physical evidence has legal implications. Evidence must be held in a secured area prior to transportation to court. Evidence reasonably assumed to have been tampered with by unauthorized persons because it was kept in an unsecured area may be inadmissible in court. Evidence should be maintained in a speciﬁc secured area, with limited access by authorized persons. Several scientiﬁc issues of proper collection and preservation of evidence require discussion. Sufﬁcient material should be collected. Judging the amount of specimen to gather is largely a matter of experience. As a general rule, however, as much material as is reasonably possible to collect should be taken. Generally, it is impractical and sometimes impossible to return to a crime scene at a later time to collect more material if more physical evidence should be needed. As a general rule, more is better than less. Many forensic science laboratory examinations compare a known specimen with a questioned specimen. Known or control exemplars are needed for these comparative laboratory analyses. For example, if a bloodstained shirt is submitted to a crime laboratory, the DNA typing results must be compared with something in order to provide useful information. A known biological sample from the victim and suspect is needed. (Some labs will use a swabbing from a subject’s mouth while others may use a blood specimen.) Similarly, if an automobile paint specimen is submitted for laboratory analysis, a known sample of paint from the questioned vehicle must be submitted for comparison. Blank samples may be important. Consider an arson investigation. An issue may be raised that heat from a ﬁre may cause wood or carpeting to give off products that might be confused with combustible material. Unburned samples of wood or carpet can be collected for testing to clarify this contention. Blank samples are used to verify that the uncontaminated samples do not interfere with the analysis. Physical evidence should be handled as little as possible. Too much handling may obliterate ﬁngerprints, dislodge minute trace evidence such as hair, ﬁbers, and debris, break apart brittle evidence, or contaminate evidence. Forceps, latex gloves, and special containers may be necessary for handling physical evidence.

© 2004 by CRC Press LLC

Figure 1.10 In this example of individualization, a receipt for payment of a monthly bus ticket (A) purchased by a murder victim was compared with a ticket found in the suspect’s home (B). The two pieces were originally part of the same ticket (C). (Institute of Forensic Science, Beijing, China.)

Crime scene investigators should have an assortment of envelopes, containers, and packaging on hand to properly collect and preserve physical evidence. Plastic bags are generally avoided. This is particularly true when preserving biological evidence such as bloodstained articles because plastic bags accelerate deterioration. However, if it is necessary to transport blood-soaked articles that cannot be air-dried at the crime scene directly to the laboratory for processing, plastic containers may be used in limited circumstances and for short periods. Airtight containers are desirable for volatile materials such as gasoline. Clean glass jars with lined screw-cap lids or clean metal paint cans with wide-mouth openings make excellent containers for arson evidence. Burned debris that is to be checked for combustible materials should never be packaged in plastic bags or plastic jars because volatile evidence will pass through most plastics. It is good practice to double-wrap very small items such as hair, ﬁbers, or glass fragments. These items should ﬁrst be folded up in a sheet of paper and then placed in an envelope. Careful packaging of minute items of evidence will ensure that they are not lost. Contamination is a concern for proper preservation of evidence. Items of evidence should be packaged separately in individual containers. Each piece of evidence should be completely segregated from other evidence. Case. A burglary suspect was apprehended near a residential tract; he had broken into a house through the rear door. The arresting ofﬁcer observed splinters, paint, and other building material on the suspect’s jacket. Samples from around the point of entry were

© 2004 by CRC Press LLC

Figure 1.10 (continued)

© 2004 by CRC Press LLC

collected for comparison and submitted with the jacket to the crime laboratory. All the evidence was packaged together in a paper bag. When it arrived at the crime laboratory, it was not possible to tell whether the debris on the jacket was from the crime scene or from the known samples collected by the investigator and placed into the bag with the suspect’s clothing. Microscopic or trace evidence presents unique collection problems. A number of techniques are available to collect this type of evidence. Vacuum cleaners specially equipped with traps can be used to collect trace evidence such as hairs, ﬁbers, glass fragments, and debris. Evidence collection vacuums are available commercially, or normal household vacuum cleaners can be modiﬁed to collect trace evidence. However, the technique indiscriminately collects relevant trace evidence as well as large amounts of debris with no relationship to the crime. An alternative method for collecting trace evidence consists of simply shaking or sweeping an item such as clothing and allowing the trace material to fall onto a clean sheet of paper. Others prefer to use cellophane tape. A 4-inch length of tape is pressed onto suspected areas and then placed, sticky side down, on a microscope slide. Each of these techniques has advantages and disadvantages. Before one technique is chosen over another, it is strongly recommended that the crime laboratory used by the police agency be consulted because the lab may prefer different practices. Specially trained personnel — forensic scientists, criminalists, forensic technicians, or identiﬁcation technicians — examine physical evidence collected at crime scenes. These practitioners are unique because they must prepare reports and testify in court as expert witnesses. Because scientiﬁc principles relating to physical evidence are often beyond the knowledge of lay people, courts permit persons with specialized training and skills to appear in court to explain and interpret scientiﬁc evidence to juries. Expert witnesses can be used when the subject of the testimony is beyond the experience and knowledge of ordinary lay people and when the expert has sufﬁcient skills, knowledge, or experience in his or her ﬁeld to help the judge or jury determine the truth. Those entrusted with the investigation of criminal activity carry a heavy burden. Although the ultimate solution of the crime is a primary goal, one cannot forget that all activity surrounding the investigation will be scrutinized at some later time. Actions taken during the investigative phase, e.g., interviews, collecting and preserving physical evidence, documenting the crime scene, etc., must be done in the proper legal fashion so that evidence can be admitted when the case goes to trial. Mistakes are often unforgiving; there are scores of examples where unintentional errors have been made that resulted in evidence being declared inadmissible by the courts. The best advice is to consider all the ramiﬁcations before taking action.

Important Considerations in Crime Scene Investigations In addition to the “how-to” elements of crime scene investigation, several other issues need to be discussed. These represent a philosophical approach to the subject and should be considered an integral part of forensic science and forensic identiﬁcation. Forensic scientists, crime scene specialists, and latent ﬁngerprint experts are the individuals whose jobs apply science and technology to the solution of criminal acts. They

© 2004 by CRC Press LLC

shoulder an important role in the criminal justice system. Their skill and knowledge in the criminal investigation may establish the innocence or guilt of a defendant. Professional ethics and integrity are essential to their effort. Many forensic specialists work for law enforcement agencies that are responsible for the criminal investigation and/or the prosecution of cases. While some may argue that employment by police agencies offers the potential for bias, in fact, it is the integrity of the professional and the organization that is the deciding factor. All forensic practitioners owe a duty to the truth. They may never be biased for or against a suspect in an investigation. The forensic practitioner’s sole obligation is to serve the aims of justice. It makes no difference whether a defendant is ultimately found guilty of the crime or not. What is important is that the forensic practitioner conducted the investigation in a thorough, competent, unbiased manner. Forensic practitioners have an obligation not to overstate or understate scientiﬁc ﬁndings. As experts in the criminal justice system, they are placed in positions of authority and responsibility. Because of their education, training, experience, and skills, their opinions on technical matters often carry considerable importance. For forensic science practitioners to perform their function within the legal system properly, they must exercise independence and integrity. Stated simply, forensic scientists cannot be biased for or against an investigation in which they are involved. Their job is to champion their own expert opinions based on accepted, properly performed scientiﬁc inquiry. Forensic scientists who understand their role in the criminal justice arena help to protect individual rights and freedoms while ensuring that justice is delivered. Like practitioners, managers of forensic science laboratories must be concerned about professional ethics. The American Society of Crime Laboratory Directors (ASCLD) adopted a code of professional practices, Guidelines for Forensic Laboratory Management Practices. They are included here as a deﬁnition of good laboratory management practices.

Guidelines for Forensic Laboratory Management Practices Introduction The American Society of Crime Laboratory Directors is a professional organization of managers and supervisors employed in forensic laboratories. We are the holders of a public trust because a portion of the vital affairs of other people has been placed into our hands by virtue of the role of our laboratories in the criminal justice system. The typical users of forensic laboratory services are not in a position to judge the quality of our work product or management for themselves. They must rely on the expertise of individual professional practitioners and the standard of practice maintained by the profession as a whole. The purpose of this document is to provide guidelines for the conduct of managers and supervisors of forensic laboratories so as to safeguard the integrity and objectives of the profession. These are not immutable laws nor are they all inclusive. Instead, they represent general standards which each manager and supervisor should strive to meet. Laboratory managers must exercise individual judgment in complying with the general guidelines in this document. The guiding

© 2004 by CRC Press LLC

principle should be that the end does not justify the means; the means must always be in keeping with the law and with good scientiﬁc practice. Responsibility to the Employer Employers rarely have the ability to judge the quality and productivity of their forensic laboratory. Therefore, the employer relies upon the forensic manager to develop and maintain an efﬁcient, high quality forensic laboratory. Managerial Competence Laboratory managers should display competence in direction of such activities as long range planning, management of change, group decision making, and sound ﬁscal practices. The role(s) and responsibilities of laboratory members must be clearly deﬁned. Integrity Laboratory managers must be honest and truthful with their peers, supervisors and subordinates. They must also be trustworthy and honest when representing their laboratories to outside organizations. Quality Laboratory managers are responsible for implementing quality assurance procedures which effectively monitor and verify the quality of the work product of their laboratories. Efﬁciency Laboratory managers should ensure that laboratory services are provided in a manner which maximizes organizational efﬁciency and ensures an economical expenditure of resources and personnel. Productivity Laboratory managers should establish reasonable goals for the production of casework in a timely fashion. Highest priority should be given to cases which have a potentially productive outcome and which could, if successfully concluded, have an effective impact on the enforcement or adjudication process. Meeting Organizational Expectations Laboratory managers must implement and enforce the policies and rules of their employers and should establish internal procedures designed to meet the needs of their organizations. Health and Safety Laboratory managers are responsible for planning and maintaining systems that reasonably assure safety in the laboratory. Such systems should include mechanisms for input by members of the laboratory, maintenance of records of injuries and routine safety inspections. Security Laboratory managers are responsible for planning and maintaining the security of the laboratory. Security measures should include control of access both during and after normal business hours.

© 2004 by CRC Press LLC

Management Information Systems Laboratory managers are responsible for developing management information systems. These systems should provide information that assists managers and the parent organization in decision making processes. Responsibility to the Employee Laboratory managers understand that the quality of the work generated by a laboratory is directly related to the performance of the staff. To that end the laboratory manager has important responsibilities to obtain the best performance from the laboratory’s employees. Qualiﬁcations Laboratory managers must hire employees of sufﬁcient academic qualiﬁcations or experience to provide them with the fundamental scientiﬁc principles for work in a forensic laboratory. The laboratory manager must be assured that employees are honest, forthright and ethical in their personal and professional life. Training Laboratory managers are obligated to provide training in the principles of forensic science. Training must include handling and preserving the integrity of physical evidence. Before casework is done, speciﬁc training within that functional area shall be provided. Laboratory managers must be assured that the employee fully understands the principles, applications and limitations of methods, procedures and equipment they use before beginning case work. Maintaining Employees’ Competency Laboratory managers must monitor the skills of employees on a continuing basis through the use of proﬁciency testing, report review and evaluation of testimony. Staff Development Laboratory managers should foster the development of the staff for greater job responsibility by supporting internal and external training, providing sufﬁcient library resources to permit employees to keep abreast of changing and emerging trends in forensic science, and encouraging them to do so. Environment Laboratory managers are obligated to provide a safe and functional work environment with adequate space to support all the work activities of the employee. Facilities must be adequate so that evidence under the laboratory’s control is protected from contamination, tampering or theft. Communication Laboratory managers should take steps to ensure that the employees understand and support the objectives and values of the laboratory. Pathways of communication should exist within the organization so that the ideas of the employees are considered when policies and procedures of the laboratory are developed or revised. Communication should include staff meetings as well as written and oral dialogue.

© 2004 by CRC Press LLC

Supervision Laboratory managers must provide staff with adequate supervisory review to ensure the quality of the work product. Supervisors must be held accountable for the performance of their staff and the enforcement of clear and enforceable organizational and ethical standards. Employees should be held to realistic performance goals which take into account reasonable workload standards. Supervisors should ensure that employees are not unduly pressured to perform substandard work through case load pressure or unnecessary outside inﬂuence. The laboratory should have in place a performance evaluation process. Fiscal Laboratory managers should strive to provide adequate budgetary support. Laboratory managers should provide employees with appropriate, safe, well-maintained and calibrated equipment to permit them to perform their job functions at maximum efﬁciency. Responsibility to the Public Laboratory managers hold a unique role in the balance of scientiﬁc principles, requirements of the criminal justice system and the effects on the lives of individuals. The decisions and judgments that are made in the laboratory must fairly represent all interests with which they have been entrusted. Users of forensic laboratory services must rely on the reputation of the laboratory, the abilities of its analysts and the standards of the profession. Conﬂict of Interest Laboratory managers and employees of forensic laboratories must avoid any activity, interest or association that interferes or appears to interfere with their independent exercise of professional judgment. Response to Public Needs Forensic laboratories should be responsive to public input and consider the impact of actions and case priorities on the public. Professional Stafﬁng Forensic laboratories must hire and retain qualiﬁed personnel who have the integrity necessary to the practice of forensic science. Veriﬁcation of academic, work experience and professional association credentials is essential. Recommendations and References Professional recommendations of laboratories and/or analysts should be given only when there is knowledge and an endorsement of the quality of the work and the competence of the laboratory/analyst. Referrals of clients to other professional colleagues carry a lesser degree of endorsement and are appropriate when a laboratory is unable to perform the work requested. Legal Compliance Laboratory managers shall establish operational procedures in order to meet constitutional and statutory requirements as well as principles of sound scientiﬁc practice.

© 2004 by CRC Press LLC

Fiscal Responsibility Public laboratories should be managed to minimize waste and promote cost effectiveness. Strict inventory controls and equipment maintenance schedules should be followed. Accountability Laboratory managers must be accountable for decisions and actions. These decisions and actions should be supported by appropriate documentation and be open to legitimate scrutiny. Disclosure and Discovery Laboratory records must be open for reasonable access when legitimate requests are made by ofﬁcers of the court. When release of information is authorized by management, all employees must avoid misrepresentations and/or obstructions. Work Quality A quality assurance program must be established. Laboratory managers and supervisors must accept responsibility for evidence integrity and security; validated, reliable methods; casework documentation and reporting; case review; testimony monitoring; and proﬁciency testing. Responsibility to the Profession Laboratory managers face the challenge of promoting professionalism through the objective assessment of individual ability and overall work quality in forensic sciences. Another challenge is dissemination of information in a profession where change is the norm. Accreditation The Laboratory Accreditation Board (ASCLD/LAB) provides managers with objective standards by which the quality of work produced in forensic laboratories can be judged. Participation in such a program is important to demonstrate to the public and to users of laboratory services the laboratory’s concern for and commitment to quality. Peer Certiﬁcation Laboratory managers should support peer certiﬁcation programs which promote professionalism and provide objective standards that help judge the quality of an employee’s work. Meaningful information on strengths and weaknesses of an individual, based on an impartial examination and other factors considered to be important by peers, will add to an employee’s abilities and conﬁdence. This results in a more complete professional. Peer Organizations Laboratory managers should participate in professional organizations. They should encourage employee participation in professional societies and technical working groups which promote the timely exchange of information among peers. These societies prove their worth to forensic science, beneﬁting both the employee and employer, through basic training as well as continuing education opportunities.

© 2004 by CRC Press LLC

Personal contacts with other agencies and laboratories with similar interests are also beneﬁcial for professional growth. Research When resources permit, laboratory managers should support research in forensic laboratories. Research and thorough, systematic study of special problems are needed to help advance the frontiers of applied science. Interaction and cooperation with college and university faculty and students can be extremely beneﬁcial to forensic science. These researchers also gain satisfaction knowing their work can tremendously impact the effectiveness of a forensic laboratory. Ethics Professional ethics provide the basis for the examination of evidence and the reporting of analytical results by blending the scientiﬁc principles and the statutory requirements into guidelines for professional behavior. Laboratory managers must strive to ensure that forensic science is conducted in accordance with sound scientiﬁc principles and within the framework of the statutory requirements to which forensic professionals are responsible.

Expert Witness Tips Forensic practitioners are often called to court to testify as expert witnesses. Testifying in court is a challenge, particularly, for an inexperienced person. Training and experience eventually make it easier. The following are some hints for effective expert witness testimony: Before Going to Court • • • • •

Keep thorough notes, records, photos, diagrams, etc. Carefully prepare your reports and consider appropriate language, completeness, and opinions. Prepare your prosecutor through a pretrial conference. Review the case before you arrive in court. Never allow a prosecutor or defense attorney to push you beyond your area of expertise or opinion. Ask yourself, can my testimony withstand the evaluation of a competent opposing expert?

Giving Expert Testimony •

• •

Dress the part of an expert. Wear conservative clothing. Avoid wearing lapel pins or jewelry that designates membership in a club, group, or religion. Your appearance carries a tremendous amount of weight in how well juries are willing to believe what you say. When answering questions, respond to the jury, not the lawyer. Talk to the jury and make eye contact. Look at the individual jurors. Sit up straight. Do not slouch or look too comfortable.

© 2004 by CRC Press LLC

• • • • • • • • • • • • •

Pause before giving your answer. Give the opposing counsel a chance to object. Also, consider what you are going to say. Try to avoid “ums” and “ahs” when speaking. Present a professional demeanor. Not only what you say is important, but also how you say it and how you look saying it. Be aware of your physical presence — how you sit, and your body language. Do not fumble with exhibits or props; watch out for change in pockets. Do not ﬁdget or sway when standing. Watch your demeanor. Do not appear too conﬁdent (it may be construed as arrogance). Avoid animosity. Appear sincere, objective, polite, and fair. Concede, if you do not know the answer. Listen to your speech, volume, and pace. Be deliberate, but not slow. Present your opinions with emphasis. Educate using nontechnical language. Use analogies. Make your testimony interesting! Concentrate: listen to every word of counsel. Do not jump the gun with your replies. Pause to clarify concepts. REMEMBER: A court reporter is recording everything you say. Be speciﬁc when giving your testimony. Respond directly to the question.

Cross Examination • • • • • • • •

The witness dictates the pace. You do not need to answer any question yes or no. Explain your rationale. Be careful with questions such as “Is it possible that …?” or “Is it fair to say?” It is acceptable to say, “I don’t believe I am qualiﬁed to answer that question.” Listen to all aspects of the hypothetical question. If you are unsure what the question is, ask for clariﬁcation. If you are not given a chance to explain your answer, ask if you can respond to clarify your statement. Remember your demeanor and attitude. You are not supposed to take sides. The louder and more belligerent the lawyer becomes, the more composed and polite you should become. Do not lose your temper. If you are asked a particularly lengthy, confusing question simply say, “I don’t understand your question. Could you rephrase it?”

Other Points • • • •

Speak in a manner that lay people can understand. Avoid jargon, especially “scientiﬁc-ese.” Go over prior testimony, reports, and exhibits before the trial. Try to have a pretrial conference with the prosecutor. Remember the KISS Principle and keep it simple! Be objective. You are not an advocate. It should not matter to you whether the case results in a guilty or not guilty verdict. Your salary will stay the same. Your job is to be an advocate for your opinion.

© 2004 by CRC Press LLC

• • • • •

• • •

Use visual aids, analogies, illustrations from everyday life, and the chalkboard. Pay attention to the judge. Objection sustained means you cannot answer the previous question. Do not box yourself into a corner. Beware of questions like, “Have you ever made a mistake” and “Isn’t it possible?” Do not try to avoid a difﬁcult question. Juries are suspicious of evasive answers. Be aware of the cross-examination trick of taking an excerpt from a publication out of context or an excerpt from a nonexistent article. You can always ask the lawyer to show you the article to refresh your memory or even to read. Be able to say, “I don’t know” or “I was wrong.” Take the lead to meet with and talk with counsel. Mentor new, inexperienced prosecutors. If he or she is new or inexperienced in a given area, be patient and offer your assistance as an expert. Try to remember how you felt the ﬁrst few times you appeared in court.

Teamwork The ﬁnal element in crime scene investigation is teamwork. The investigation of criminal acts involves scores of people who often work for different agencies. This system was purposefully designed so that no one person or entity can operate independently. As such, turf issues will always arise — This is my responsibility; you are not supposed to do that. In addition, as we move to larger and more complex criminal justice systems, we are more likely to be dealing with people who are faceless voices at the other end of the telephone. For any complex systems to work, teamwork is essential. Each element of the criminal investigation —uniformed ofﬁcer, detective, crime scene specialist, forensic scientist, coroner, forensic pathologist, photographer, prosecutor, plus all the other vital players in the “system” — must work cooperatively with the other elements to make the entire process work. No one element or person is more important than any other person or element. Each person has a vital role to play and each portion of the case must be accomplished in a responsible, professional and timely manner to make every component function properly. Everyone working on a case should feel that he or she is essential to the successful completion of an investigation. Each must feel empowered to do what needs to be done, if only for the sake of justice. Prima donnas have no place in this process! This chapter has introduced some of the major concepts concerning physical evidence, including its deﬁnition and value, the difference between identiﬁcation and individualization, a brief discussion of the collection and preservation of physical evidence, ethical conduct, and teamwork. Subsequent chapters will explore these topics in greater detail as they relate to speciﬁc types of evidence and investigations.

Professional Development Crime scene investigation, forensic identiﬁcation, and forensic science require continuing education and networking with other professionals. It is unthinkable, for example, that a physician, dentist, accountant or lawyer would not maintain ongoing study though

© 2004 by CRC Press LLC

professional conferences and continuing education. This is equally true in the forensic science professions. Law enforcement agencies employ most crime scene investigators and forensic identiﬁcation and forensic science professionals. Many police agencies fund continuing education in their annual budgets at amounts between $1000 and $1500 per testifying practitioner. This economic commitment is essential to the ongoing professionalism of practitioners and is used for professional association dues, professional conferences, and continuing education. The International Association for Identiﬁcation is one of the oldest professional associations of its kind. For professionals engaged in crime scene work, it is an excellent vehicle to maintain competency in this ﬁeld. The IAI publishes the Journal of Forensic Identiﬁcation and holds an annual seminar that brings colleagues together to attend workshops and technical presentations and to exchange information. The IAI is worthy of consideration for membership for any serious practitioner. Many state divisions of the IAI also may be explored.

© 2004 by CRC Press LLC

First Ofﬁcer at the Crime Scene

2

The Case of the Lady in Cement In late 1987, the skeletal remains of a middle-aged woman, unceremoniously labeled “Jane Doe No. 9,” were found buried in the foundation of a residence in the Paciﬁc area of the city of Los Angeles. Examination indicated she had died of multiple stab wounds. The upper portion of her body was encased in cement, a factor that led to her identiﬁcation through a variety of unusual scientiﬁc measures. The wet cement that had ﬂowed over her body had settled in a vivid outline of her skull. This allowed the composite artist of the Los Angeles Police Department, Scientiﬁc Investigation Division, to cast a death mask of the victim. The mask and artist’s rendering presented a startling likeness to the victim, who was ultimately identiﬁed (Figure 2.1). When the drawing appeared on television a citizen produced a photograph of a woman resembling the drawing. This led to the possible name of the victim. A ﬁngerprint card was found on ﬁle because she had been ﬁngerprinted for a routine job application. Her arms, crossed over her body, left telltale ﬁnger holes in the cement where her hands had rested. Portions of the cement were surprisingly smooth textured, leading to speculation that the preservation of ﬁngerprint evidence might be possible. After experimenting with various substances, the Latent Print Section determined that rubber silicone was superior because of its high tensile strength and other properties necessary for detail enhancement. Silicone was carefully poured into each hand mold and allowed to dry. The cast was then painstakingly removed from the mold. The silicone casts bore ridge detail of the ﬁngers and palm that enabled the Latent Print Section to make a positive identiﬁcation of the victim. Just as dramatic were the casts’ clearly deﬁned additional cuts and stab wounds on her hands and ﬁnger, probably as a result of defending herself at the time she was attacked by her killer (Figure 2.2). Meanwhile, the concrete-walled grave in which the victim was found also contained items of clothing and other artifacts. The Comparative Analysis Unit © 2004 by CRC Press LLC

Figure 2.1 Wet cement had ﬂowed over the victim’s body creating an outline of her skull (A), which allowed the LAPD composite artist to cast a death mask (B) of the victim. The mask and artist’s rendering (C) presented a likeness of the victim.

was able to pin down a meaningful estimate of an entombment date to provide detectives with a time frame in which to target their investigation. They determined that the most likely item found with the body for dating was a partly deteriorated cigarette package. The name of the manufacturer, Liggett & Myers (L&M), was discernible. A partial reconstruction of the deteriorated package was necessary to determine additional package characteristics, such as the style, color, location, and content of the imprinted information, tax seal dimensions, and package components. Detailed photographs were taken to record the pertinent information.

© 2004 by CRC Press LLC

Figure 2.1 (continued)

As part of a test market in March, 1974, in the Liggett & Myers western region (California, Arizona, New Mexico, Colorado, Nevada, Idaho, Montana, Wyoming, North and South Dakota, Washington, Oregon, and Utah) the company had introduced a soft pack of L&M “longs.” The product was withdrawn in March, 1975, and the L&M packaging was changed. Furthermore, the tax-stamp dimensions, afﬁxed to a package by the local wholesaler, were consistent with the type used in California (Figure 2.3). This narrow time frame of 1 year, bracketed by March, 1974, and March, 1975, when the cigarette package was marketed and probably purchased, helped detectives

© 2004 by CRC Press LLC

Figure 2.1 (continued)

target a suspect who had access to the house during that time span. Although other items of evidence were available and dramatically important in this particular case, the cigarette package clearly demonstrated the hidden potential of physical evidence. Murder charges were ﬁled against the suspect.

The First Ofﬁcer at the Scene Crime scenes are dynamic, rapidly changing environments and the ﬁrst ofﬁcers to arrive on the scene must be concerned with countless details. To a great extent, the success of the investigation and, perhaps, the chance for a successful resolution of the case hinge on actions and steps taken by the ﬁrst ofﬁcer to arrive at the crime scene.

© 2004 by CRC Press LLC

Figure 2.2 The silicone casts contained sufﬁcient detail on the ﬁngers and palm to enable a positive identiﬁcation of the victim. The casts also clearly showed additional cuts and stab wounds on her hands and ﬁnger, a result of defending herself at the time she was attacked by her killer.

The crime scene is the locale from which the majority of the physical evidence associated with the crime is obtained. It provides investigators with a starting point for the inquiry to determine the identities of the suspect and victim and to piece together the circumstances of what happened during the crime. Physical evidence found at the scene can be the key to the solution of the crime. The ﬁrst ofﬁcer’s most important task at the scene is to prevent the destruction or diminished value of potential evidence that may lead to the apprehension of the criminal and the ultimate resolution of the crime. The responsibility of the ﬁrst uniformed ofﬁcers at the scene should not be minimized. What these ofﬁcers do or do not do, whether innocent or intentional, may have serious consequences to the investigation. Some police agencies have very speciﬁc policies for uniformed personnel concerning their duties and responsibilities at the crime scene. First responders should be familiar with those duties and responsibilities and execute their jobs to the best of their ability. Superior ofﬁcers and training ofﬁcers should monitor the performance of both new and experienced uniformed personnel. Police agencies should

© 2004 by CRC Press LLC

Figure 2.3 The concrete-walled grave also contained items of clothing and other artifacts. One artifact was a partly deteriorated cigarette package showing the name of the manufacturer, Liggett & Myers (L&M). L&M had test marketed a menthol long cigarette soft pack in March, 1974, in their western region, which included California. The product was withdrawn in March, 1975. (Los Angeles Police Department.)

understand the importance of ongoing training and continuing education, not only for investigative and technical personnel, but for ﬁrst-responding personnel as well. The duties of the ﬁrst ofﬁcer to arrive at the crime scene are the same, regardless of the rank, and remain the same regardless of the seriousness of the crime. The ﬁrst responder at the scene must assume that the criminal left clues or physical evidence. The ﬁrst responder’s actions or inactions should not destroy or change anything at the scene. Information developed from evidence left at the scene may help to reconstruct the crime or prove the identity of the suspect. Furthermore, the ﬁrst ofﬁcer must not inadvertently add material that may mislead investigators. Common sense strongly suggests that a crime scene will yield useful information. It is not possible for anyone to enter a place without changing it in some way, either by bringing something to it or removing something from it. The idea of a person changing a scene is known as the Locard Exchange Principle. Although changes to a crime scene may be exceptionally small, the course of an investigation may well hinge on their detection. Therefore, the ﬁrst ofﬁcer’s action or inaction may affect the future of the investigation. The value of detailed, meticulous note taking throughout all phases of the case cannot be overemphasized. All ofﬁcers have many jobs to perform during the beginning phases

© 2004 by CRC Press LLC

of an investigation. Police handle many investigations and it is not inconceivable for one case to blur into another — a very human reaction. Thorough, detailed note taking, i.e., recording signiﬁcant as well as mundane observations at the time they are noticed, is the most effective way to minimize loss of information. Naturally, a general rule of protecting the crime scene cannot be applied in every case. The resources of the individual law enforcement agency as well as the nature of the crime must be taken into account. Petty thefts and similar misdemeanors will not receive the same in-depth investigation as a case involving murder, rape, or assault. Some police agencies may arbitrarily set a lower limit to the property value lost in a burglary as a way to determine the scope of their investigation. In certain serious crimes, it may not be possible to preserve the crime scene because of the location. A busy street or highway with heavy trafﬁc is an example of a situation in which it may not be possible to protect a crime scene properly for a sufﬁcient period of time. In situations like this, the deciding factor in safeguarding the crime scene concerns the likelihood that the criminal has left clues that can be recovered vs. the negative factors of holding up trafﬁc ﬂow. Each case must be decided on its own merits. At ﬁrst glance, the actions to be taken by the ﬁrst ofﬁcers on the scene may seem simple and not well beyond the scope of routine police duties. Some further examination of these duties will show that this is not the case. First of all, ﬁrst responders should not approach the scene in haste. All movements should be calm and deliberate. Ofﬁcers should expect the worst and take the position that it is better to be overly cautious and remember the popular wisdom: if something can go wrong, it will! Approaching the assignment with an open mind helps an ofﬁcer avoid carelessness and false moves that may prove to be disastrous. Mistakes made during the interrogation and other aspects of the preliminary investigation can perhaps be corrected; but errors committed in the protection and examination of the crime scene may never be set right. The eventual success of the investigation may be dependent on the preventative and preliminary measures taken by the ﬁrst ofﬁcer to arrive at the crime scene. Unfortunately, there are too many examples of how an omission or a mistake on the part of the ﬁrst responder proved fatal to the investigation and resulted in an unsolved crime. In a difﬁcult situation, the ofﬁcer may be faced with a dilemma that requires quick analysis of the circumstances and taking appropriate steps. However, if the basic rule of always anticipating the worst and taking extensive rather than minimal precautions is followed, the most serious errors can usually be avoided. Because conditions and situations can vary greatly from one crime scene to another, it is not possible to set hard and fast rules. However, certain guidelines can be established. These are mainly applicable to homicide cases and other serious crimes because it is in just these cases that the ofﬁcer is faced with the most difﬁcult tasks and the actions taken have the most far-reaching consequences. These rules are applicable to less serious crimes as well.

Recording the Time Precise notations of the time are very important in an investigation. They are most important for checking a suspect’s story and can often be quite important in other consequences

© 2004 by CRC Press LLC

as well. Therefore, the ﬁrst ofﬁcer at the scene should write down arrival times and other times that may turn out to be important. Notation should be made of the time that the crime was committed, the time that the ofﬁcer was ﬁrst called, the time of arrival at the scene, and so on. Such notations lend precision and credibility to the ofﬁcer’s statement if testifying in court should become necessary. Keeping track of the time spent at the scene also maintains a chronological record of the way things were done during the crime scene investigation. These notes will prove invaluable if speciﬁcs about the investigation should be needed after the actual event.

Entering the Scene Proper When entering the scene, the ofﬁcer should try to form an estimate of the situation — what happened here — as quickly as possible. This estimate is the basis for any subsequent actions. When entering the scene proper, or the focal point of events, the ofﬁcer must proceed with extreme caution and concentrate attention on possible evidence that may be found on doors, doorknobs, light switches, ﬂoors, and other areas. An effort must be made to observe details, particularly those that are ﬂeeting, and to take written notes on such points as: • • • • • • •

Doors — open, closed, or locked? On which side was the key? Windows — open or closed? Were they locked? Lights — on or off? Which lights were on? Shades, shutters, or blinds — open or closed? Odors — cigarette smoke, gas, gun powder, perfume, etc.? Signs of activity — meal preparation, dishes in the sink, house clean or dirty, etc.? Date and time indicators — mail, newspapers, dates on milk cartons, stopped clocks, spoiled foods, items that should have been hot or cold but were at room temperature

Nothing at the crime scene should be moved initially unless absolutely necessary. The crime scene should remain as close as possible to its original condition when the detective or investigating ofﬁcers arrive. If it becomes necessary to remove any object because others may disturb it, the ofﬁcer should consider the possibility that the item may have ﬁngerprints present and act accordingly. Before any object is moved, its location should be noted. The exact position of an object at a scene may become important later in the case. Its position should be noted in the report, outlined in chalk, sketched, photographed, or videotaped. Under no circumstances should anyone be allowed to wander about the crime scene simply to satisfy his curiosity or pick up and handle objects. Regrettably, there have been too many instances where ﬁrst ofﬁcers arrived at the scene and toured it, leaving ﬁngerprints on a variety of surfaces. Such carelessness cannot be tolerated. Those at the crime scene should not use the toilet, turn on water, eat, drink, smoke, or use towels. The criminal may have used any of these objects — a towel could have been used to wipe a bloodstained weapon. Evidence may have been caught in the sink trap. The rule is simple: the ﬁrst ofﬁcer at the crime scene should not touch anything unless absolutely necessary or unless he is charged with the responsibility of processing the scene for physical

© 2004 by CRC Press LLC

evidence. First ofﬁcers should consider it embarrassing to have their ﬁngerprints found and identiﬁed at the crime scene. First ofﬁcers should understand that they may be called on later by the investigator or detective to account for every movement made at the crime scene. This may be necessary in order for the investigating ofﬁcer to get a better idea of the original condition of the crime scene proper or to explain seemingly out-of-place items at the scene. On occasion, the victim or a relative may attempt to clean up the scene — perhaps to put everything in proper order when the police arrive or to try to conceal something. Occasionally, cleaning serves a psychological need to put everything back in its place. If a clean-up is in progress when the ofﬁcer arrives, it should be stopped. If the clean-up has been completed or the ofﬁcer suspects that is the case, a detailed inquiry should be made to determine the original condition of the scene. It may be possible to recover material or undamaged items that were thrown out.

Protecting the Integrity of the Scene As soon as possible after arriving, the ofﬁcer should take steps to protect the scene from anyone not directly involved with the investigation, including other ofﬁcers, supervisors and command personnel, the press, curiosity seekers, and family members. This is no easy task and sometimes requires some ingenuity because, initially, personnel may be insufﬁcient to protect the crime scene (Figure 2.4). Simply locking a door or stringing rope or commercially available crime scene tape around the perimeter can secure the crime scene. If these measures do not sufﬁce, ﬁrst responders may resort to using vehicles, boards, or furniture gathered from another area away from the scene to help keep curiosity seekers out. Even with devices such as police barricades, yellow crime scene tape, and ropes, ofﬁcers may still need to take an active role in keeping unauthorized people away. The extent of any protective measures must be decided on a case-by-case basis. As a general rule, if the scene is indoors, the barricade should include the central scene and, where possible, the probable entry and exit paths used by the criminal. In this connection, it is important to focus attention on potential evidence on the ground outside a window, in rooms through which the criminal had to pass, in stairways, or in entrances. If the location is outdoors, an ample area should be roped off to include the paths taken by the criminal to and from the crime scene proper. Sometimes, critical evidence may by found on or near a route leading to or away from the scene. It is important to search paths carefully. In some cases, prior to the arrival of the police, onlookers trample the crime scene. In open areas, a dependable barricade can be set up only if an ofﬁcer is stationed outside the perimeter. The protection of the scene in this case merely requires that the ofﬁcer not walk around aimlessly inside or immediately outside the roped-off area. Limiting movements permits later accountability for the ofﬁcer’s own tracks. The ﬁrst ofﬁcer should remain at the scene whenever possible and should send others to call headquarters or detective personnel. Leaving the supervision of the crime scene to persons other than police ofﬁcers should only be done in exceptional circumstances. Protective measures at the scene should be taken as early as possible to prevent valuable, often vital evidence from being destroyed. It is also important that barricades be sufﬁciently

© 2004 by CRC Press LLC

Figure 2.4 Uniformed ofﬁcers must take care when securing the scene. This ofﬁcer did not and consequently superimposed his shoe prints over those of the suspect. (Los Angeles County Sheriff’s Department.)

extensive from the beginning of the investigation. Sometimes, a sufﬁcient area around the crime scene is not protected early enough in the investigation. When large outdoor areas are to be protected, ofﬁcers may take the initiative by enlisting the aid of police cadets, police reserves or others who can be trusted to assume responsibility for protecting the scene.

Injured Person on the Scene Saving lives is the ﬁrst priority and takes precedence over all other considerations. If an injured person is on the scene, ﬁrst aid should be administered immediately even if it means valuable evidence may be lost or destroyed. If ﬁrst aid to the injured is not immediately essential, the ofﬁcer should note the victim’s position on a simple sketch, by marking the ﬂoor, or by forming a mental picture of the position. The ofﬁcer should note how the victim is lying or sitting, the position of the hands, arms, and legs, the condition of clothes, and so on. It is also important to notice if the victim’s hands have anything in them such as hairs, ﬁbers, etc. When paramedical or emergency medical personnel arrive, the ofﬁcer should — without interfering in their work — instruct them how to enter the scene without disturbing

© 2004 by CRC Press LLC

it unnecessarily. Observing the movements of medical personnel and noting whether any objects were moved is a necessary task. If civilian emergency medical personnel transport the injured person, a police ofﬁcer should accompany the victim. An alert investigator may hear an important word or accusation or what might be equivalent to a dying declaration that might be the key to the entire case. In one case, a dying woman uttered the name of her assailant. This vital information fell on the untrained, inattentive ears of the civilian emergency medical personnel and no amount of interviewing could sharpen their recall. The ofﬁcer should arrange for proper removal and custody of the victim’s clothing. Occasionally, when the hospital or mortuary is contacted to obtain the victim’s garments, the clothing has been incinerated or wadded into a hopeless mess after being cut from the body. Representatives of police agencies should make periodic visits to local hospitals to instruct medical personnel in the proper handling of evidence. The medical profession’s lack of interest in and knowledge about evidence is disheartening, considering the broad range of their training and the media attention to criminal investigations.

Dead Person on the Scene If the ﬁrst ofﬁcer on the scene is able to establish certain signs of death, such as clear rigor mortis, odor, lividity, beginning decomposition, and so forth, the body is not to be touched or removed until a detailed examination can be made. Once the ﬁrst ofﬁcer at the crime scene has established that the victim is dead and has made a cursory inspection of the crime scene, superiors must be notiﬁed regarding the nature of the case. A telephone should be used for this purpose rather than a police radio because it is not uncommon for the press and other news sources to monitor police radio frequencies.

Summoning the Coroner Whether the medical examiner or coroner should be contacted at this point of the investigation is a matter of local custom. Some agencies, by agreement with the coroner or medical examiner’s ofﬁce, ﬁrst wait for the investigating ofﬁcers to arrive and begin their investigation. Notiﬁcation of a death may be made at this time, with an estimate of the time the coroner should arrive. This can save the coroner’s staff time by not having to wait needlessly at the scene until the police have completed their portion of the investigation. Policies should be arranged with the medical examiner’s or coroner’s ofﬁce on such call-out matters. The medical examiner–coroner’s or coroner’s ofﬁce generally has jurisdiction over the body at the crime scene. Where this jurisdiction is in effect, the body may not be moved or searched without prior consent of the medical examiner–coroner. On rare occasions, the ﬁrst ofﬁcer must take immediate steps to remove the body from the scene. In these situations, the ofﬁcer must ensure that the deceased is placed on the stretcher in the same position in which the body was discovered, provided that circumstances permit. Limbs rigidly ﬁxed in a certain position should not be straightened. If the victim is found face down, the body should remain in that position because lividity may change position and appearance, and trickles of blood may change direction.

© 2004 by CRC Press LLC

If the rigidity must be broken in order to transport the body, the ofﬁcer must make note of it, preferably with sketches or photographs showing the original position. Before the body is moved, its position must be marked on the ﬂoor, on a sketch and photographed. It is important that the position of the head, arms, hands, knees, and feet is shown on the sketch. The ofﬁcer should also note the condition of the clothes and bloody tracks that may be present. This can be extremely important in answering the question of whether the body had previously been moved. Blood may run while the body is being removed. A question may later arise about the source of this secondary ﬂow of blood.

Suspicious Death A woman was found dead on the ﬂoor in her bedroom. The ﬁrst ofﬁcer at the scene made a superﬁcial examination of the scene. Some of the deceased’s relatives stated that the woman had been very ill. Concluding that she had died of natural causes, the ofﬁcer had the body removed from the scene without examining it further. After the deceased was moved, it became apparent that she had died of strangulation. A scarf had been tightly wound around the neck three times and knotted at the throat. A trickle of blood had run over one cheek from the mouth in an upward direction in relation to the position of the head at the time of the brief examination. The investigation of the case was complicated and impossible to decide because of the ofﬁcer’s premature decision to allow the body to be removed. It never could be established whether the blood ﬂowed during or before transportation.

In cases of strangulation or hanging where unmistakable signs of death are observed, the ﬁrst ofﬁcer at the scene should do nothing to the body. If there is a danger that the rope might break, the ofﬁcer may attempt to support the corpse, but it should not be cut down. If obvious signs of life are present, the ofﬁcer must try to save the person. Knots in ropes should not be untied, if possible. The knot may be typical of a certain occupation or skill level. The noose may be cut and the loose ends labeled appropriately. An alternative to labeling is to tie the ends back together with string or thread. If these materials are not available, the noose or rope should be placed so that the ofﬁcer can later recall which ends belong together. In emergencies, the knot may be loosened somewhat and the noose pulled over the victim’s head. It is also important to remember which end of the rope was anchored to a ﬁxed object or pulled over a branch or beam. The direction of distorted surface ﬁbers on the rope may indicate whether the victim was pulled up because it is always possible that a hanging was arranged to cover up a murder.

Firearms and Ammunition on the Scene The general rule is that any ﬁrearms or ammunition should be left untouched until investigating personnel arrive. However, recovery of weapons and ammunition may become necessary. If they may be inadvertently moved or lost during the removal of an

© 2004 by CRC Press LLC

injured person, or if conditions are such that the ﬁrst ofﬁcer cannot effectively protect the scene alone and bystanders might disturb the evidence, then the evidence may be removed. When weapons are recovered, the ofﬁcer should concentrate on the possibility that valuable evidence may be found on cartridge cases as well as on weapons. If there is reason to believe that ﬁngerprints are present in oil or grease on a weapon found at an outdoor crime scene in cold weather, the weapon should not be moved to a heated room; the heat may destroy the evidence. When picking up pistols and revolvers, a pencil or a stick should never be inserted into the barrel in order to lift the weapon. Dust, blood, particles of tissue, and other debris in the barrel may become dislodged. To move a hand gun, grasp the checkered surface of the grips with two ﬁngers to lift the weapon. Fingerprints will not be deposited on the grips. If the grips have a lanyard ring attachment, the gun can be lifted by the ring. Before the weapon is recovered, its position should be marked on a sketch or by outlining its position on the ﬂoor. This marking is important. There might also be a mark in the ﬂoor under the weapon, indicating that the gun fell from the hand of a suicide. The position of bullets and cartridge cases may reveal the direction of the shot and possibly the location of the assailant. The positions of hammer and safeties should be noted (Figures 2.5 and 2.6).

Suspicious Death A man with a bullet wound in his head was found in his apartment. A police ofﬁcer and emergency medical personnel transported the dying man to a hospital where he was pronounced dead on arrival. The ofﬁcer accompanied the injured person to the hospital, which complicated the investigation because the ﬁrst ofﬁcer was not available to communicate any information to detectives, who immediately began an investigation of the apartment. A bullet and cartridge case were found in the room where the victim had apparently been shot, but a weapon was not located. An automatic pistol was found on a shelf in the hallway and appeared to have been recently ﬁred. A suspicion of murder arose because the injured man could not have placed the gun there. Thus began a thorough and time-consuming examination of the apartment. After the ﬁrst ofﬁcer who had gone to the hospital was questioned, the case was determined to be a suicide. The ﬁrst ofﬁcer had found the gun by the victim and, without thinking of the consequences, examined it and placed it on the shelf before leaving the apartment. If the investigators had known the facts from the ﬁrst witness — the ﬁrst ofﬁcer — much time and effort could have been saved. Certainly, the detectives acted properly by assuming the worst; however, the ﬁrst ofﬁcer at the scene failed to brief the investigators adequately.

If a weapon is found, it should be in the same condition in which it was recovered when delivered to a ﬁrearms examiner for examination. When the ﬁrearm is packaged for submission as evidence, a detailed description of what was done to it may be prepared and sent to the crime laboratory. The ﬁrst ofﬁcer should not pull the slide back on a pistol or turn the cylinder of a revolver, nor touch the trigger or the safety catch. The only

© 2004 by CRC Press LLC

Figure 2.5 A suspect discharged a weapon in a Fairbanks, Alaska, nightclub and subsequently ﬂed, discarding the gun in the snow. A previously convicted felon was interviewed about the crime but denied any knowledge or ownership of a weapon. A latent print was developed using cyanoacrylate ester and photographed using direct reﬂective lighting. The felon’s prints were compared with a latent print on the trigger and identiﬁed. He was charged with “Felon in Possession of a Firearm.” (State of Alaska, Scientiﬁc Crime Detection Laboratory, Latent Print Section.)

acceptable changes to the weapon would be to remove a cartridge from the chamber or mark the position of the cylinder. Only a person with ﬁrearms experience should render the weapon safe.

When a Suspect Is Found at the Scene The ﬁrst ofﬁcer to arrive at a crime scene may need to arrest or detain a suspect. In such cases, the most important duties should be done ﬁrst. The police ofﬁcer must use common sense in taking whatever measures are necessary in order to protect the scene. If it is not possible to hold the suspect at the scene or in the police vehicle, a possible alternative is to ﬁnd a reliable person to protect the scene until other ofﬁcers arrive. The ﬁrst ofﬁcer must instruct such persons on how to guard the premises because the task is likely to be unusual for them. The ﬁrst ofﬁcer should also be aware that the longer the suspect remains at the crime scene, the greater the possibility becomes of changing or contaminating the crime scene. The suspect could, for example, remove evidence, leave new evidence or even gain

© 2004 by CRC Press LLC

Figure 2.6 This latent print was developed with cyanoacrylate fuming. The 30.30 caliber bullet was recovered from inside a loaded riﬂe magazine; the crime involved the shooting death of an elderly white male. The photographic technique employed “shadow” photography and inner negative reversal of the ridge color. The reader is referred to the article on shadow photography in the Journal of Forensic Identiﬁcation 38(5) Sept./Oct., 1989. (State of Alaska, Scientiﬁc Crime Detection Laboratory, Latent Print Section.)

information from the opportunity of observing the scene in detail. The suspect should be searched and removed from the location as quickly as possible.

What to Do Until Investigating Personnel Arrive While waiting for investigators to arrive, the ofﬁcer should attend to the following: •

• •

•

Write down names of witnesses and other persons who entered the scene. This is important for the subsequent sorting of ﬁngerprints and other clues found at the scene. Note who was at the scene when the ofﬁcer arrived. This information can become particularly important if the crime has just occurred. Establish the basic facts. A factual account of what happened is of great assistance to the detectives when they arrive because it helps them decide on the next move. However, the ofﬁcer should never undertake lengthy and detailed interrogations that may damage later questioning or give rise to misleading suggestions in the statements of witnesses. Furthermore, the ofﬁcer cannot properly guard the scene if occupied with interrogations. Keep the suspect and witnesses separated wherever possible. Allowing the suspect and witnesses to talk may interfere with later questioning. Family members may

© 2004 by CRC Press LLC

•

•

• •

be left in the care of neighbors when necessary, taking care that no alcoholic drinks or sedatives are administered. Remember that the dramatically grieving relative may be the prime suspect. Instruct witnesses not to discuss the events. This can prevent distortion by suggestion. If possible, the principal witnesses should be separated. In relating events to one another, witnesses may distort each other’s impressions to a point at which they believe that they saw things that they really did not see or that never happened. Do not discuss the crime with witnesses or bystanders. This is also intended to prevent suggestion and distortion. Furthermore, circulating details of the crime may hinder the investigation. Listen attentively, but unobtrusively. An alert ofﬁcer can often pick up information of vital importance to the investigation simply by being a good listener. Protect evidence that is in danger of being destroyed. During inclement weather such as rain or snow, divert water and cover tracks with boxes, cardboard, etc. If the crowd of onlookers becomes large, it may become necessary to expand the protective measures at a given location to prevent trampling of the evidence.

When the investigating ofﬁcers arrive, the ﬁrst ofﬁcer should report all that has been learned and observed and the actions taken. This is very important to the evaluation and planning of the crime scene investigation. It is particularly important that reports be given of the extent to which the scene has been altered and whether objects have been disturbed or moved.

Continued Protection of the Scene In protecting the scene after the investigators have arrived, the ofﬁcers detailed to protect it should act only on orders from the detective in charge. During the technical examination of the scene, it is the crime scene investigator who is in charge of the ofﬁcers on security duty as well as of the scene proper. No one should be allowed access to the crime scene without the investigator’s permission, not even other investigators or superior ofﬁcers. Command ofﬁcers would render a ﬁne service to their investigators if they would preserve the integrity of the crime scene with a passion and set an example for other ofﬁcers by keeping out of the scene. Those allowed on the scene must move with their hands in their pockets so as not to touch anything. Through carelessness or without even being aware of it, they may touch objects on the scene. The explanation might be that a desire to do something prompts them to touch objects that should not be touched before they have been examined. Wearing gloves should not be permitted at the crime scene (except in cases where quantities of blood or other biological ﬂuid is present and infectious diseases are a concern). People wearing gloves are more likely to become careless and touch objects that may have ﬁngerprints and thereby destroy them or render them useless. Unfortunately, there are numerous instances of police ofﬁcers on sightseeing tours through crime scenes. Sometimes they destroy more evidence than any group of lay people could possibly accomplish. At one crime scene, it was reported that the presence of one more police ofﬁcial would have threatened the collapse of the building. Even experienced

© 2004 by CRC Press LLC

Figure 2.7 The suspect stated that he had never been in the murder victim’s house in Ninilchik, Alaska. Trash from the victim’s wastebaskets was examined for latent prints. A print was developed on the ring tab of a beer can using cyanoacrylate ester fuming. The latent print was compared to and identiﬁed with the suspect in the case. (State of Alaska, Scientiﬁc Crime Detection Laboratory, Latent Print Section.)

investigators are guilty of allowing these tours, especially in murder cases and other serious crimes. News reporters sometimes arrive at the scene before the ofﬁcers who are to examine it. People in the neighborhood usually call them or they may have heard a call on the police radio. The ﬁrst ofﬁcers on the scene should not, under any circumstances, give information about the case to reporters. To inform the press is the responsibility of the police chief, sheriff, or ofﬁcers designated by them. Ofﬁcers should not favor one reporter or news agency by giving out information that may not be available to the competitors through prescribed channels. In dealing with reporters, ofﬁcers should be neither curt nor nonchalant, but they should be ﬁrm, even when reporters are persistent. The ofﬁcer should remember that reporters often give invaluable assistance in the investigation of major crimes. Press passes should be disregarded during the protection of a crime scene.

© 2004 by CRC Press LLC

Crime Scene Dos and Don’ts Do Limit access to the crime scene by using tape and a major incident log. Attempt to identify possible routes used by the suspect. Note original conditions at the crime scene. Record changes in conditions especially in regard to your activities (or paramedics’). Protect evidence from adverse environmental conditions. Conduct all administrative duties outside the tape (coffee drinking, smoking). Record the location of evidence before moving it. Package trace evidence (paint, glass, etc.) into large envelopes. Keep an open mind as to what might be evidence. Be aware that you are a potential source of evidence. Take photographs of items at 90r with and without L-scales. Call expert personnel to crime scenes for detailed or difﬁcult collection or documentation. Take photographs of all aspects of crime scenes, perspective shots, 90r photos of items and bloodstains.

Don’t Permit unnecessary personnel to enter the crime scene. Use routes possibly used by the suspect. Assume others will note original conditions, etc. Fail to document any changes or contamination at the scene. Allow evidence to be compromised by nature Eat or use any facilities or the phone within the crime scene. Remove items and package without documentation. Package trace evidence in a bundle. Ignore items that appear out of place or are difﬁcult to explain. Touch anything unnecessarily. Photograph items only without scales. Assume the expert can always answer the questions from nonexpert collection or documentation. Limit your photos to overalls and item locations.

This list was developed by Ronald Linhart and Elizabeth Devine, Los Angeles County Sheriff’s Crime Laboratory.

© 2004 by CRC Press LLC

3

The Crime Scene Investigator

Case The body of an 18-year-old female was found on the side of a road near Porvoo (a small city about 50 km northeast of Helsinki, Finland). The deceased was completely naked from the waist down and the upper part of her body was clothed normally. The victim’s jeans, stockings and underwear were bundled on her chest. The technical research team took the clothing of the deceased, ﬁngernail scrapings, head hair and pubic hair combings, and known hair standards as samples. Fiber evidence was found in the victim’s hair. The autopsy determined that the cause of death was strangulation and that the victim had been raped. Semen was found in vaginal and rectal samples taken during the autopsy and the ABO blood group A was determined. The victim’s blood group was type A. The hope of solving the case centered on the ﬁber evidence and an initial hypothesis was made that the ﬁbers must have had something to do with the crime. Eleven brown uniform and multicolored acrylic ﬁbers were found from the combed hair samples. Similar ﬁbers were collected from tape lift samples taken from the clothes of the victim. About 200 ﬁbers were found in the clothes. With the help of reference samples, it was deduced that these ﬁbers most probably originated from the seat cover of a car. The police were advised that the laboratory was especially interested in brown automobile seat covers made from a pile-type material and that, while searching cars, they should give special attention to red textiles (Figure 3.1). From the samples combed from the victim’s head and pubic hair, two and three thick viscose ﬁbers were found, respectively, that were unusual in their color and dyeing. The victim’s clothes yielded 28 similar ﬁbers. In the combed samples an orange-red woolen ﬁber was found that was about 3 cm long; 13 similar ﬁbers were found in the clothes. Because of the number of red-colored ﬁbers found, it was possible to consider primary transfer. It was assumed that the origin of the ﬁbers must have been from a textile other than clothes worn by the suspect because neither of the ﬁber types belonged to typical cloth textile types (Figure 3.2). The technical research team examined 12 cars over a 2-month period. They collected seat covers that were a possible match to the ﬁbers, picked hairs and © 2004 by CRC Press LLC

Figure 3.1 (A) The roadside near Porvoo where the body was discovered; (B) the body was discovered partially clothed; (C) a close-up of the victim.

© 2004 by CRC Press LLC

Figure 3.1 (continued)

Figure 3.2 The police eventually located the suspect’s car, partly because of leads the laboratory was able to provide concerning the seat cover.

© 2004 by CRC Press LLC

Figure 3.3 (A) A search of the suspect’s home yielded ﬁbers similar to those found on the victim; (B) ﬁbers from the fabric on the couch and woolen blanket on the sofa proved to be important evidence in the criminal prosecution.

ﬁbers, taped the seats and searched for the victim’s ﬁngerprints. The ﬁber samples taken from the victim did not match the samples taken from these cars. The victim’s clothes were white and light blue and made mainly of cotton; therefore, it was pointless to try to collect these types of ﬁbers. The 13th car to be examined belonged to a person who, 9 years earlier, had been charged with rape but released due to insufﬁcient evidence. The suspect was also a type A secretor. The seat cover material in his car matched the acrylic ﬁbers from the hair and the clothes of the victim. Also, the samples taken from the seat covers contained similar red-colored viscose and woolen ﬁbers found on the samples taken from the victim. Thirty-nine samples were taken from the interior furnishing textiles in the suspect’s residence and also from his clothes. The red viscose ﬁbers proved to be the same as the pillowcase cloth ﬁbers found on the sofa in the living room of the suspect’s residence. The red woolen ﬁbers were the same as ﬁbers from a blanket found on the sofa (Figure 3.3). The samples taken from the victim’s hair, pubic hair, ﬁngernail scrapings, and clothes were compared with the ﬁber samples taken from textile materials in furnishings in the suspect’s residence and from his clothes. The victim’s hair yielded 13 dark blue cotton ﬁbers; one of the same type was found in her ﬁngernail scrapings. These ﬁbers could not be differentiated from the ﬁbers taken from the suspect’s blue trousers. In the clothes of the victim, three thick yellowish-brown V-shaped viscose ﬁbers were found. Their color, quality, thickness, shape, and size were the same as plush ﬁbers found on a velvet sofa cover in the suspect’s residence. The sixth ﬁber similarity between the samples taken from the victim and samples taken from the suspect’s residence was pink acrylic ﬁbers, of which three found in

© 2004 by CRC Press LLC

Figure 3.3 (continued)

the victim’s clothes were similar to the ﬁbers of a sweater in the suspect’s residence. All of the different types of ﬁbers were found in the suspect’s car seat cover and clothing. During the investigation, it was concluded that the victim had not been to the suspect’s residence but the suspect’s untidy habits transferred the ﬁbers from his residence to his car, which was a secondary transfer. None of these ﬁbers were found at the victim’s residence, on her clothes, or at her mother’s home. Polarizing light microscopy, ﬂuorescence microscopy, and microspectrophotometry were used in the ﬁber identiﬁcation. FTIR spectroscopy was used to investigate the brown acrylic ﬁbers. The accused did not confess to the crime but admitted that only he used his car. He was convicted and sentenced to 10 years on the basis of evidence produced by the ﬁber investigation.

Most police departments today use uniformed or patrol divisions as well as detectives in crime scene processing. The patrol ofﬁcer, who is usually the ﬁrst police ofﬁcer to respond to the crime scene, and the detective, who may arrive later, are responsible for the investigation and processing of the crime scene. This division of labor by function is useful because it allows for a certain degree of specialization and hence the likelihood of better performance in the respective responsibilities. Although patrol or detective personnel may be used for crime scene processing in serious crimes, many police agencies delegate to detectives and/or specialists, such as crime scene investigators, ﬁngerprint specialists, or forensic scientists, the crime scene search and collection and preservation of physical evidence. Patrol or uniformed ofﬁcers may process crime scenes in less serious crimes. Uniformed ofﬁcers often respond to residential burglary scenes to investigate the crime,

© 2004 by CRC Press LLC

take a report, photograph the crime scene, dust for latent ﬁngerprints, and collect evidence, without calling a detective or using specialized personnel such as crime scene evidence technicians. However, in major criminal investigations — such as homicides, rapes, assaults, and robberies — personnel with more extensive training and experience are most likely to be used in processing crime scenes. Although different law enforcement personnel may process the crime scene, the rules are the same in all cases. Crime scenes contain potent information that, if sought in a systematic, legal, and scientiﬁc way, can help the investigator determine what happened, who was responsible, and who was involved. Law enforcement personnel involved in criminal investigations must be able to derive the maximum possible information from the crime scene. The objectives of a crime scene investigation are to: • • • • • • •

Reconstruct the incident Ascertain the sequence of events Determine the mode of operation Uncover a motive Discover what property was stolen Find out all that the criminal may have done Recover physical evidence of the crime

In some cases, the investigation yields results that point directly to the criminal and provide solid evidence against the offender. Generally, this happens when the perpetrator’s ﬁngerprints are found at the scene and the prints are already on ﬁle. Such cases happen infrequently, but the use of AFIS, Automated Fingerprint Identiﬁcation Systems, has greatly improved the chances of identifying the criminal and many cold cases have been solved through AFIS technology. The work of crime scene investigators1 is frequently thankless. Often the public and police ofﬁcers think of them as a modern day incarnation of Sherlock Holmes or one of several popular characters on television portraying crime scene investigators. Some expect that real-life crime scene investigators are capable of magically establishing complete information on the identity of the criminal and solving the crime quickly, as television is able to do within the hour allotted to the usual TV show. When a crime scene investigator does not succeed in doing just that, he may be considered unsuccessful. This attitude is, of course, ridiculous. It is the duty of detectives to pursue and apprehend the criminal; the duty of the crime scene investigator is to gather all evidence available at the scene. For the investigative process to function best, the detective and the crime scene investigator need to work cooperatively. Each must consider the other as part of the team. The notion of teamwork in criminal investigations is a key factor to a case’s solution. Each person in the process plays a vital role. Any one individual can do something that has disastrous consequences to a case or makes a signiﬁcant contribution. No one, including the uniformed police ofﬁcer, the detective, the forensic specialist, the medical examiner, or the prosecutor, can fulﬁll his duty without the cooperation and assistance of all the other people on the team. 1 As used in this chapter and elsewhere in this book, the term “crime scene investigator” refers to a specialist whose principal job is to identify, collect, and retrieve physical evidence from the crime scene or to a detective or investigator who has the collateral duty of collecting and preserving physical evidence.

© 2004 by CRC Press LLC

Crime scene investigators understand that criminals leave trace evidence behind and take away minute material from the scene and/or victim. The crime scene investigator’s job is to ﬁnd these traces and preserve them. Such evidence may be used to reconstruct the crime or to prove that the suspect committed a criminal act. The value of any item of evidence to a criminal investigation — such as an apparently unimportant object or fact — may turn out to be extremely important later in the investigation. No item, however small, should be overlooked. The crime scene investigator’s job at the scene is similar to that of the ﬁrst police ofﬁcer to arrive on the scene. Each must proceed calmly and deliberately. The crime scene investigator should not approach the task with preconceived ideas or draw premature conclusions. Investigators should scrutinize the scene with their eyes open for details. Experience teaches the investigator to expect the worst2 and to be more thorough than needed. A good rule to remember is: It is better to have processed the scene more thoroughly than needed than to have overlooked something seemingly insigniﬁcant that later turns out to be a critical item of evidence in the investigation. A complete investigation may produce information that substantiates a confession or refutes a defense contention raised at the trial. Mistakes made during the investigation often may never be rectiﬁed. Naturally, making the statement, “investigations should be conducted as thoroughly and carefully as possible,” belies the fact that investigators are only human. Even experienced, dedicated professionals make mistakes. Remember that conducting thorough investigations is a goal for which to strive. Even with the best of intentions, mistakes and oversights may occur. The O. J. Simpson case is a classic example of how the actions of investigators can be misconstrued. During the trial, the defense team raised questions about the crime scene practices of the police and even cited a prior edition of this textbook to suggest that the police acted improperly in processing the scene. An important lesson from this case is that appearance and perception, as well as the ability to communicate effectively to a jury, are equally important. Appearances and perception are every bit as important as knowledge, skills, and ability, at least in the eyes of the jury and the public. If the defense can make it appear that evidence was handled in an improper manner, the jury may agree. There are few absolute rules in crime scene investigations. An important concept to note is that most rules outlined in this text and others are guidelines, based on common sense, that are applied to crime scene investigation. There are always cases where guidelines cannot be followed. An example is packaging wet, bloody evidence in plastic trash bags. Wet, biological evidence packaged in plastic bags deteriorates more quickly than air-dried evidence and should not be used. However, when faced with a crime scene with bloodsoaked clothing or bedding, separate packaging in a clean plastic trash bag for immediate transportation to a crime laboratory is an appropriate way to handle such items if the evidence cannot be dried at the scene. Situations demand that investigators be ﬂexible and creative when necessary. Because investigators are human beings, it is impossible for them to conduct investigations without making mistakes. It is necessary to try to make as few errors as possible and to learn from past faults. Unfortunately, critics will always have a compelling urge to 2 Those new to crime scene investigations will do well to consider the wise sayings found in the folk wisdom of Murphy’s Law: 1) If something can go wrong it will and 2) If there is a worst time for something to happen, it will, at that time!

© 2004 by CRC Press LLC

be “Monday-morning quarterbacks” and advise any who will listen about how something should have been done. An investigator would be wealthy if he could have a dollar for each time he said, “If only I had thought to collect that item of evidence” or “I should have done ‘thus and so’ a different way” or “Why didn’t I think of that at the time; it seems so obvious now.” The adage that “hindsight is always 20–20” is a fact of life. Through experience, the same mistakes should not be made again. It is a good practice to ask if anything more should be done before quitting a crime scene. A further lesson to be learned from the Simpson case is that the focus of forensic science is shifting from the laboratory to the crime scene. The crime scene investigation process is taking on a more prominent role. Defense attorneys are quick to learn that, if they can show that the initial handling of the physical evidence at the crime scene was faulty and calls into question subsequent lab work, the evidence may be kept out of the trial or at least tarnished in the eyes of the jury. Crime scene investigators should not allow superiors or others at the scene to inﬂuence their deliberations on the case before or during the actual crime scene examination. The investigation should not be rushed, if possible. Others must wait. The investigator is personally responsible for his mistakes and has the right to determine personal actions at the scene. An experienced crime scene investigator asked to explain how he proceeds at a scene may ﬁnd this difﬁcult to explain. Each crime scene is different and it may not be possible to lay down absolute rules for conducting an investigation; however, a generalized outline on how to process a scene can be made to ﬁt a vast number of conditions. No matter how experienced an investigator is, there are always new situations to be faced and completely unfamiliar problems to master. The best advice to give in an extraordinary situation is to be calm, adaptable, and ﬂexible. The essential qualities of a good crime scene investigator are intuition and an eye for what needs to be done in every individual case, along with a thorough knowledge of the methods of locating and preserving physical evidence. Before any actual work at the scene begins, an investigator should try to stand back at an appropriate vantage point on the periphery of the scene and formulate a systematic plan, considering: • • •

How the search should be conducted What needs to be photographed at the scene Where the possible sources of physical evidence are

Following this initial assessment, the crime scene investigation can begin. The start of the crime scene investigation begins with documenting the scene. This process includes: • • • •

Photography and/or videotaping (overall views) The investigation of the crime scene proper (when needed, combined with photography and videotaping detailed views) Sketching (detailed sketches may be required during the investigation) Note taking (to be done throughout the investigation — constant interruptions for notes are the rule)

© 2004 by CRC Press LLC

Figure 3.4 (A color version of this ﬁgure follows page 256.) Computer-aided drawing (CAD) programs continue to gain wide use in crime scene documentation. They provide an effective tool for investigators and aid juries in understanding the crime scene. (Los Angeles County Sheriff’s Department.)

Note taking at a crime scene is essential. Well-written, contemporaneous notes are invaluable later in the investigation and especially at the time of trial. It can be extremely frustrating for an ofﬁcer assigned an old open case if the case notes of the original investigator’s initial observations are inadequate or even shoddy. There are no substitutes for good note taking at all phases of the investigation. The order in which work is done at a scene is not sacrosanct. The rule is to be ﬂexible and to use common sense. Sometimes an investigator must examine a detailed part of a scene or make a sketch of an object that had to be moved immediately on arrival at the scene. Consequently, the order of the various phases of processing a crime scene must be decided on a case-by-case basis. Investigators should adopt an air of curiosity about everything concerning the crime scene, even the smallest items. The perpetrator may have forgotten or dropped something. A seemingly innocuous item may become the decisive piece of evidence later in the investigation. All investigators should develop a healthy skepticism. Things often are not what they seem to be. Be critical and never accept conditions or appearances without ﬁrst

© 2004 by CRC Press LLC

questioning them. Simulated crimes or crimes masquerading as accidents to cover up criminal activities do take place.

Actual Examination of the Scene Investigators should think through and reconstruct the actions of the criminal. If the reconstruction does not make sense or if there are inconsistencies, consider starting over to reevaluate the sequence of events. One way to proceed is to eliminate scenarios while reasoning that “it couldn’t have been done this way.” Continue the process until one or two possibilities remain. A useful suggestion is to carry a few pieces of chalk or crayons in the crime scene equipment kit. If it becomes necessary to move an object, the location of the object can be marked with chalk, pencil, or crayon. Examining an outdoor crime scene at night should be avoided, unless there is a compelling reason. Daylight, outdoor crime scene searches are more effectively examined, yield more information, and are easier to conduct. If an outdoor search must be conducted at night using artiﬁcial lighting, the scene should be kept intact as long as possible for a ﬁnal search in daylight. No matter how powerful the lighting equipment, daylight is better. Experience teaches that some evidence, invariably missed in artiﬁcial light searches, is more readily detectable in daylight. A crime scene investigation should not start if it is obvious that specialized personnel need to be called in to take over the job. The crime scene specialist’s task is complicated enough and does not need to be made more difﬁcult by the necessity of ﬁnishing what someone else began. The specialist should be permitted to take charge of the intact crime scene after being fully briefed by the detective in charge of the investigation. This guarantees the best possible results. “Two heads are better than one” — using two crime scene investigators to search for and collect physical evidence is the most effective stafﬁng level for most major crime scene investigations. A single crime scene investigator can do an effective job of searching for and collecting physical evidence, but two are better. Two investigators are more thorough. Notwithstanding this recommendation, in some instances just one investigator will sufﬁce. Emergency circumstances and small, limited crime scenes are such examples. The crime scene investigator may call on an ofﬁcer who has experience in photography to photograph the scene. Similarly, the investigator may use uniformed police and detectives as assistants to help with some of the simpler tasks. However, this practice should only be used when temporary assistants can be supervised closely and given detailed instructions. The two crime scene investigators should be used to working on crime scenes together and should be able to cooperate. They should work as a team rather than on separate tasks. One way to divide the work is for one investigator to do the actual examination while the other keeps notes and assists by making personal observations, making measurements and helping to examine a particular area. Two persons, working together, are able to observe much more than a single person can. Whatever one of the investigators discovers should immediately be reported to the partner. They also should discuss the different possibilities of how a certain clue might have been left at the scene and how the criminal proceeded. An idea that might not occur to one person may well occur to a second.

© 2004 by CRC Press LLC

In homicide cases and other serious assaults, crime scene specialists should not assume any other investigative duties. Their full attention should be devoted to the case in order to get the most from their efforts. If crime scene work and the detective functions are combined, one of the activities, typically the crime scene duties, usually suffers. Specialized personnel assigned to crime scene duties must cooperate closely with the detective in charge. This division of labor between duties of specialists personnel and detectives may not always be possible due to a lack of personnel. However, the two types of work should be separated whenever feasible. On arriving at the scene, the crime scene investigator should ﬁrst obtain the basic facts from the ofﬁcers already present. It is important that crime scene investigators be well briefed about the case before starting their examination of the scene. Arrival times and weather conditions should be noted. It is also important to determine which persons had prior access to the scene and whether any changes in the original conditions occurred. When entering the crime scene, investigators should proceed cautiously, aware of potential clues on ﬂoors, doorknobs, light switches, and other areas that may have been touched by the criminal. Even when chances are slight that evidence may be found, investigators should not dismiss the possibility that important evidence is present. Investigators should never walk about the crime scene aimlessly. They should exercise the same caution that is expected from inexperienced personnel. Even if many people have already trampled the crime scene, it is important to watch one’s step. Although it might be excusable for untrained ofﬁcers to destroy evidence by inadvertently handling items or stepping on items of evidence, such actions are unpardonable for experienced crime scene investigators. Before starting work, investigators should ﬁrst thoroughly consider the crime scene. Signiﬁcant circumstances may be overlooked if the scene is not thoroughly evaluated ﬁrst. The investigator should make a complete and systematic survey of the scene and its immediate surroundings, both indoors and outdoors. The investigator should attempt to reconstruct the actions of the criminal by constantly asking “why and how?” Why did the criminal do this, how was the building entered, how was this mark made? Distractions should not be allowed to interfere with the investigator’s initial reconstruction of the case. Quiet deliberation is essential to planning the course of the investigation intelligently and getting the most information out of the scene. Everything crime scene investigators learn during the investigation should be written down as it is discovered. Clear, concise, contemporaneous notes should be taken during the entirety of the examination. The location and description of objects should be recorded in the notes before they are moved or examined in detail. In some cases, before moving an item of evidence, it is helpful to make a detailed sketch and take close-up photographs with a scale or ruler in the photograph. Examination notes at the crime scene should be made in the order of the work done and should not be edited. Any editing and report writing should be done after the initial stage of the investigative process and, preferably, back at the ofﬁce. The extent of the notes is somewhat proportionate to the seriousness of the crime; a burglary investigation may not merit as many detailed notes as a murder investigation. In the murder case, the statute of limitations never runs out, so notes must be complete enough to be understandable and helpful even 15 or 20 years later. 3 All objects and details pertinent to the description of the scene must be noted. The report of the investigation of a major crime can never be too detailed. The completeness of the report

© 2004 by CRC Press LLC

is especially important in crimes that are not solved within a reasonable time. Rough notes and sketches made at the scene should never be discarded but included with the case ﬁle. Although the press has a legitimate role in reporting criminal activity, the media should not be permitted into the crime scene proper to photograph the actual scene without express permission from the ofﬁcer in charge. In sensational crimes, news photographers will often try to photograph the crime scene and victims, along with police ofﬁcers. Police personnel should not pose for such pictures; they usually look ridiculous. These news photographs only serve the doubtful purpose of satisfying the public’s desire for sensationalism. Personnel at the crime scene should never divulge speciﬁc information or conditions at the crime scene to reporters. In fact, only public affairs ofﬁcers or lead detectives should speak to reporters at crime scenes. The general rule is not to give out essential information, which is key to the solution of the crime. Usually, only the criminal gains from these news accounts. In one high-proﬁle serial murder case, at a press conference the mayor of a large U.S. city released critical information about unique shoe prints found at several crime scenes. Needless to say, those shoes were never located when the suspect was apprehended. Suspects in a criminal investigation may claim that they learned about particular facts relating to the case on television or in the newspapers. Such information should be given to the press only if it would assist the investigation, and only the ofﬁcer in charge or a superior may give permission for its release. In cases in which the press becomes privy to sensitive information, they should be asked to hold off reporting it to the public in the interest of solving the case. If paramedics have been called to the scene, they must be allowed to enter the crime scene whenever an injured person is present or when death has not been established with certainty. The crime scene investigator should ensure that paramedics do not unnecessarily destroy evidence. If unmistakable signs of death (rigidity, lividity, odor, beginning decomposition, etc.) are present, paramedics need not be called. Once the ﬁrst phase of the investigation has been completed, the coroner may be called. Investigators should work to cultivate good working relationships with their medical examiner and coroner’s representatives. Close cooperation between the police and the coroner is requisite for successful investigations. A crime scene investigation is characterized by three essential conditions for success: organization, thoroughness, and caution. Confusion, incompetence, and imprudence may result in a failed investigation. Following the initial attempt at reconstructing the crime scene, the crime scene investigator’s task is to photograph the central crime scene.4 The actual investigation should follow with the central scene, unless an initial survey indicates that physical evidence is present along the route used by the criminal to enter or leave and this evidence cannot be well protected. In such cases, the investigator should ﬁrst examine and recover these items

3

The advent of forensic DNA typing and AFIS technology has had an interesting side effect. Murders committed 15 and 20 years ago are being solved. Computer systems storing DNA results and unidentiﬁed ﬁngerprints wait patiently for a “hit.” Unidentiﬁed criminals, whose DNA is tested and added to states’ felon DNA databases or prints entered into AFIS databases because of an unrelated arrest, have been identiﬁed and many unsolved cases cleared, often to the criminal’s surprise. 4 The terms “central crime scene” and “crime scene proper” are interchangeable and refer to the area where the crime took place.

© 2004 by CRC Press LLC

of evidence before continuing at the central crime scene. The search of the criminal’s route should start from the central scene. In an indoor homicide scene, the central crime scene can be searched beginning with the criminal’s suspected point of entry and point of exit, followed by the area adjacent to the body, and ﬁnishing with the rest of the room. Crime scene investigators should attempt to work according to an established routine that does not vary greatly from case to case. This helps to reduce the risk of overlooking a seemingly insigniﬁcant article of trace evidence or a larger object that the perpetrator may have left behind or accidentally dropped. Investigators should not start the crime scene investigation with a detailed examination of the body until the basic examination of the scene has been completed. Other aspects of the crime scene may require attention ﬁrst. Also, if investigators form a clear picture of the circumstances of the case by ﬁrst examining the scene, the examination of the body might provide more information. Unknown facts may be discovered that are of value in relation to ﬁndings on the body. A preliminary inspection of the body to suggest the mode of death can precede the crime scene search. Noting a gunshot wound suggests that bullets or cartridges may be present. If investigators expect it will take a great deal of time to complete the initial crime scene search, body temperature and other time-of-death indicators should be collected. Sometimes it is helpful to leave signiﬁcant objects in their original positions during the investigation to aid in reconstructing the crime. This practice is useful if the reconstruction of events or the logical steps of the reconstruction do not mesh. If this happens, start over and retrace the steps in the thought process. The body should not be moved in haste if its presence is needed for the reconstruction. In some cases, it may even be appropriate to leave the corpse overnight, but consideration should be given to the availability of the forensic pathologist. If the autopsy can be performed right away, it should take place as soon as possible after the body’s position is recorded. However, if the only purpose for moving the body is to place it in storage at a mortuary, this would be an error. Mere consideration of the dead should not inﬂuence the decision to move the body if further study at the crime scene is required. At the very start of the investigation, investigators should designate an area as a “trash pile” in which things may be put that should not be lying about the scene. A certain amount of waste normally accumulates from empty ﬁlm packs, blood-testing materials, etc. A work area is needed for ﬁlling out evidence tags, developing ﬁngerprints on small objects, handling casting material, and so on. Although it is not proper to smoke at a crime scene, the rule is not inﬂexible, particularly when investigators are forced to work for long periods of time. The trash collection point should be located as far away as practical from the central crime scene. Spreading a newspaper or using a paper trash bag and marking it accordingly is enough to establish the trash pile. For special methods of detecting, preserving, and evaluating evidence found at the crime scene, the reader is referred to subsequent chapters that deal with methods used at different kinds of crime scenes.

© 2004 by CRC Press LLC

Specialized Personnel at the Crime Scene

4

Uniformed ofﬁcers and detectives do not possess the full range of special skills and expertise needed to process an entire crime scene. A wide range of specialized support personnel — some employed regularly and others occasionally — can provide these talents when called into a crime scene investigation. Sometimes a particularly serious case may warrant outside assistance, such as hazardous material specialists in the case of clandestine drug laboratory cases or federal authorities (e.g., Federal Bureau of Investigation, Bureau of Alcohol, Tobacco, and Firearms, or Drug Enforcement Administration) when investigating mass disasters, terrorist acts, bombings, or major ﬁres. Crime scene investigation (CSI) ofﬁcers and evidence technicians are police or civilian personnel specially trained to process a crime scene.1 These persons are equipped to collect and preserve physical evidence at a crime scene. They arrive at the scene with evidence collection kits and all tools and equipment needed to conduct the search and collect the evidence thoroughly. There is no single classiﬁcation of personnel or a sole way in which crime scene personnel are represented in public safety organizations. Some police departments employ identiﬁcation (ID) ofﬁcers. The ID ofﬁcers photograph the crime scene and search for latent ﬁngerprints; they may not be responsible for collecting other types of physical evidence at the crime scene. ID ofﬁcers are generally experts in ﬁngerprint collection and sometimes ﬁngerprint comparison. They may be subpoenaed as expert witnesses to establish the identity of the suspect by comparison of latent ﬁngerprints with inked prints. Some cases may require an accurate architectural rendition of the crime scene. Forensic surveyors or other specially trained crime scene personnel may be used for this purpose. Relying on accurate measurements, notes, sketches, and photographs, they produce an architectural-like drawing of the crime scene for use at the trial. In some instances, threedimensional models of the scene may be prepared to better assist the prosecution in presenting the case (Figure 4.2). Today, it is quite common to use computer programs to make accurate drawings of crime scenes. Photographers are used for specialized photography. Aerial photographs may be needed to illustrate outdoor crime scenes. Unusual photographic problems such as low

1 The International Association for Identiﬁcation (IAI) offers a well-regarded certiﬁcation program for crime scene investigators. More information is available at their web site: http://www.theiai.org/.

© 2004 by CRC Press LLC

Figure 4.1 (A color version of this ﬁgure follows page 256.) Crime labs frequently use standard cars, trucks and vans specially outﬁtted as crime scene vehicles. (Los Angeles County Sheriff’s Department.)

levels of light, infrared photography, or aerial infrared photography may require their expertise (Figure 4.3). Forensic photographers as well as police photographers are utilizing digital photography more for general police photography as well as crime scene photography. The increased resolution and decreased cost of digital cameras is driving this change. Considerations remain to be made before adopting digital cameras in lieu of ﬁlm photography, but it is likely that, in a few years, digital photography will be the dominant still imaging technology in crime scene photography. Videotaping is used by some law enforcement agencies as a means of recording crime scenes. Although affordable video units are available, the level of training required to take quality videos goes beyond the skills of a home hobbyist. Specialists require training to operate and maintain the sophisticated equipment necessary and to produce quality crime scene videotapes. The criminalist, or forensic scientist, has special training and education in chemistry and biology that is applied to the recognition, identiﬁcation, collection, and preservation of physical evidence. The criminalist is typically called on to assist in more serious criminal investigations such as homicides, assaults, bombings and arson. A criminalist’s special area of expertise in these cases is trace evidence, biological evidence, and crime

© 2004 by CRC Press LLC

Figure 4.2 A three-dimensional mock-up of one of the crime scenes from the infamous Hillside Strangler Case in Los Angeles, California.

scene reconstruction. In addition to assisting at the crime scene, criminalists conduct laboratory tests on the evidence, prepare reports, and testify as expert witnesses on their ﬁndings. State and local jurisdictions utilize a coroner system or a medical examiner. No standardized system is in place across the U.S.; however, most would argue that forensic pathologists have the training preferred for performing autopsies in criminal cases. The purpose of the medical examiner or coroner system in death investigation is twofold: to determine the cause of death and to identify the deceased. The forensic pathologist or a trained investigator from the medical examiner’s ofﬁce is almost always called to the scene of a homicide as soon as the police investigator has completed the initial examination of the scene. It is the medical examiner’s responsibility to identify the deceased, determine the approximate time of death, and take custody of the remains. Ideally, the forensic pathologist or coroner’s investigator should be present at the crime scene to conduct an initial examination. Hospital emergency room personnel may play an important role in gathering evidence in criminal investigations. Doctors and nurses who treat rape or assault victims often are required to collect physical evidence relating to the assault. Hospital emergency room personnel may not know which evidence is important or the legal requirements of evidence collection. The ﬁrst ofﬁcer to arrive at the scene of a rape, for example, may be required to inform the emergency room physician what evidence needs to be collected. Forensic nurses are a relatively new group of professionals who provide a valuable resource to the police. They have training in nursing and in proper evidence collection as well as in other criminal justice-related skills. Today, most are found in hospital emergency room settings and collect sexual assault evidence as part of their duties. Expect to ﬁnd more of them in other medical settings where evidence is collected for criminal investigations (Figure 4.4).

© 2004 by CRC Press LLC

Figure 4.3 Photographic techniques using different lighting techniques can sometimes help to visualize important evidence. Writing discovered on the top inside portion of a drawer (A) was barely visible under normal lighting (a color version of this ﬁgure follows page 256). (B) Reﬂected infrared lighting enhanced the writing, making the telephone number visible. (Los Angeles County Sheriff’s Department.)

© 2004 by CRC Press LLC

Figure 4.4 An aerial view of an arson ﬁre at Universal Studios in Los Angeles, showing the extent of the devastation. (Los Angeles County Sheriff’s Department.)

The district attorney may sometimes become a member of the crime scene investigation team. He or she may be called upon to obtain a search warrant for a location under investigation or a court order to obtain known specimens from a defendant. In special cases, a forensic dentist may be called to a scene. Mass disasters such as plane crashes or scenes where charred remains are discovered require the expertise of forensic dentists to assist in identiﬁcation by means of dental remains. They also may be called upon to collect and preserve bite-mark evidence on a victim or on foodstuff. If the crime scene is a burial site, the assistance of a forensic anthropologist may prove valuable. The evaluation of skeletal remains at the scene is important in some instances. Also, excavating a grave site requires skill; experts with such experience can be helpful (Figure 4.5). Cadaver dogs are specially trained to recognize the scent of decaying remains. They are useful for searching an area where investigators believe a body was buried to conceal a decedent. Forensic psychologists are available to assist in evaluating a crime scene. One important group of trained personnel is through VICAP (violent criminal apprehension program). In cooperation with law enforcement agencies throughout the U.S., the FBI has raised VICAP to an important resource for crime solving. The agency is in the forefront of psychological proﬁling techniques and has trained hundreds of detectives across the country to review cases involving solved or unsolved murders or attempted murders. VICAP is appropriate in cases that involve an abduction and seemingly random, motiveless, or sexually oriented crimes or in known or suspected serial crimes. VICAP may be called in for missing person cases in circumstances in which foul play is suspected.

© 2004 by CRC Press LLC

Figure 4.5 A team of arson investigators and crime laboratory personnel examine the scene of the Universal Studios ﬁre (note the use of the video recorder to document the crime scene). (Los Angeles County Sheriff’s Department.)

Forensic engineers may play a role in studying the structural integrity of a building or other structure in an accident investigation. Sometimes, an item of building material may require engineering tests to determine if it was tampered with. Forensic engineers can be helpful in electrical ﬁres, explosions, vehicle examinations involving trafﬁc accidents, and investigations involving aircraft. Forensic audio specialists may be required to evaluate sound recordings or to assist in reconstructing events by means of studying sound recordings of an event. Sometimes echoes can be used to pinpoint the location from which a weapon was ﬁred. Forensic toxicologists may become involved in product tampering cases to determine the nature of the adulterant in the foodstuff or consumer product. Using sophisticated laboratory instruments, they may be able to examine products for unknown poisons or other contaminants. The Society of Forensic Toxicology (SOFT) deﬁnes three distinct elements of forensic toxicology as: •

Postmortem forensic toxicology, which determines the absence or presence of drugs and their metabolites, chemicals such as ethanol and other volatile substances, carbon monoxide and other gases, metals, and other toxic chemicals in human ﬂuids and tissues, and evaluates their role as a determinant or contributory factor in the cause and manner of death

© 2004 by CRC Press LLC

Figure 4.6 (A color version of this ﬁgure follows page 256.) New technology such as this SCENESCOPE“ ultraviolet light imaging system can assist crime scene technicians to visualize trace evidence, such as latent prints that ﬂuoresce under ultraviolet light. (SPEX Forensics www.scenescope.com.)

•

•

Human-performance forensic toxicology, which determines the absence or presence of ethanol and other drugs and chemicals in blood, breath or other appropriate specimens, and evaluates their role in modifying human performance or behavior Forensic urine drug testing, which determines the absence or presence of drugs and their metabolites in urine to demonstrate prior use or abuse

Firearms examiners are often called to assist in a crime scene to recover spent bullets from walls and doors and to assess the trajectory of ﬁred weapons. They may also assist in determining whether a shooting could have been an accident or was more likely to have been intentional. A consistent theme throughout this textbook is that police investigation is a team approach; professionals with multidisciplinary expertise are routinely brought together to solve crimes. It is not possible for a police investigator to have complete knowledge of the law, forensic science, and forensic medicine, as well as other training specialties needed to process a crime scene and investigate a crime completely. Investigators should maintain lists of local experts who can be readily mobilized to assist in cases. Such a directory is a major asset for successful police work. The need for teamwork cannot be overemphasized. Throughout the case, the detective in charge will be responsible for pulling together a vast array of information from many sources. The detective’s leadership skills are key to getting the maximum amount of information from those that may have been associated with the case from the crime scene portion of the case onward. Investigators who take the time to work closely with their

© 2004 by CRC Press LLC

Figure 4.7 (A) Hazardous materials are an ever-present possibility at crime scenes. Here, investigators suit up to enter a murder–suicide crime scene involving hydrogen cyanide gas (El Cajon Police Department Crime Laboratory, El Cajon, California). (B) Hazardous materials are regularly found at clandestine drug laboratories such as this methamphetamine laboratory (a color version of this ﬁgure follows page 256). (Los Angeles County Sheriff’s Department.)

© 2004 by CRC Press LLC

Figure 4.8 An improvised explosive device was delivered by the U.S. Postal Service to the victim’s mailbox. The victim stated that she opened the mail box and found a lacquered wooden box tied with a blue ribbon with a card on top. When she removed the ribbon and opened the box, the bomb exploded. The photograph is a reconstructed version of the bomb that was used to produce a list of the items used in construction of the bomb. (U.S. Postal Service.)

experts and maintain close working relationships with them will be rewarded by the extra effort.

Health and Safety Issues at Crime Scenes The threat of chemical and biological terrorism as well as potential exposure to diseases at crime scenes requires unique expertise, which is sometimes not considered by police professionals. The following material is presented as a precaution. Awareness and proper care could save a life. Chemical or Biological Terrorist Crime Scenes2 We live in a strange world where the unthinkable can become a reality. Because the threat of chemical and biological (as well as radiological and nuclear) terrorism is a reality and police and crime scene personnel may be called on as ﬁrst responders, it is necessary to discuss this subject. 2

Contact your local FBI ofﬁce if you suspect you are dealing with a terrorism case.

© 2004 by CRC Press LLC

(A)

(B)

Figure 4.9 Commercially available devices can assist in documenting the crime scene. (A) A protractor used to measure the angle of a ﬁred bullet through a door and (B) a laser mounted on a tripod are two ways to depict trajectory. (EVI-PAQ, http://www.evipaq.com.)

Ultimately, federal agencies, such as the Federal Bureau of Investigation, the Department of Homeland Security, the Department of Defense, Centers for Disease Control, and other organizations will be brought into a situation. However, local public safety agencies will be the ﬁrst responders on the scene and ﬁrst to assess the situation. The following information is a cursory overview. Pre-incident planning and preparation are essential for personal safety in weapons of mass destruction, or WMD, situations. 3 3

The subject of ﬁrst responders at WMD scenes is a very ﬂuid topic. There are some excellent web sites for further information; see, for example: http://www.wmdﬁrstresponders.com/Index.htm.

© 2004 by CRC Press LLC

Figure 4.10 Body parts may be discovered in uninhabited areas, sometimes as a result of wild animal activity. A forensic anthropologist may be of assistance in developing information concerning identity from a skull. (Los Angeles County Sheriff’s Department.)

Indicators of a Possible Biological Terrorist Threat •

• • • • • •

Any reference to the terms “biological,” “bacteriological,” “germ,” “microbe,” “microorganism,” “virus,” “fungi,” “bug,” “vaccine,” “antidote,” “culture,” “spores,” or “vector” Any reference to the use of toxins, venoms, or poisons in relation to the development or use of weapons Any attempt to purchase or obtain information concerning biological cultures or spores from medical or research facilities Any information concerning the theft or attempted theft of biological cultures or spores from a university or medical research facility Any purchase or consideration to purchase laboratory supplies or specialized medical equipment Any attempt to acquire vaccines or medical antidotes against poisons or disease Any attempt to acquire any type of protective breathing apparatus or protective plastic, rubber, or charcoal-impregnated suit (these protective suits are not needed for biological agents)

© 2004 by CRC Press LLC

•

• •

•

•

• •

Any indication of possession of, or an attempt to acquire, maps, photographs, or other information related to a public water supply, such as water treatment plants, reservoirs, or storage tanks Any reference to addresses of medical research facilities or mail-order companies Any indication of possession of, or attempt to acquire, maps, photographs, or other information related to architectural, building, or security plans of medical research facilities, including universities and private labs Any indication of the existence of an unusual infectious disease or other medical condition such as anthrax, botulism, or staphylococcal enterotoxemia in a locality where such a condition is not prevalent Any evidence of suspicious medical research activities, such as reports of rats, mice, rabbits, sheep, goats, or eggs at an incongruous location; the death of a large number of such animals in any locality; or the unexplained existence of medical protective garments, gloves, or medical face masks Any type of explosive device that contains an unexplained powder or liquid substance Any attempt to acquire meteorological data, such as temperature, humidity, or wind conditions, or any other relevant data contained in current weather forecasts

Indicators of Possible Chemical Terrorist Threat •

• • • • • • • •

•

• •

Any reference to the terms “chemical agent,” “nerve agent,” “blood agent,” “blister agent,” “choking agent,” “mellowing agent,” “incapacitant,” “GA,” “GB,” “GD” “GF,” “GH,” “VE,” or “VM” Any reference to the use of oxidizers, bleaches, or other decontaminates Any unexplained attempt to purchase bulk chemicals Any indication of an interest in the location of chemical manufacturing, storage, or distribution sites Any information concerning the theft or attempted theft of a tanker truck containing hazardous chemicals Any purchase of, or consideration to purchase, chemical-related laboratory supplies or equipment Any attempt to acquire antidotes against chemical nerve agents, such as atropine Any attempt to acquire any type of protective breathing apparatus or protective plastic, rubber, or charcoal-impregnated suit Any indication of the possession of, or an attempt to acquire, maps, photographs, or other information related to a public water supply, such as water treatment plants, reservoirs, or storage tanks Any indication of the possession of, or an attempt to acquire, maps, photographs, or other information related to architectural, building, or security plans of chemical manufacturing, storage, or distributing facilities Any unexplained report of individuals suffering from the symptoms of exposure to chemical agents, such as chemical burns or muscular seizures Any indication of unexplained or suspicious chemical accidents or spills

© 2004 by CRC Press LLC

• •

Any type of explosive device that contains an unexplained powder, solid, liquid, or gaseous substance Any attempt to acquire meteorological data, such as temperature, humidity, or wind condition, or any other relevant data contained in current weather forecasts

The nature of these crimes makes it imperative that law enforcement personnel appreciate the hazards of biological and chemical terrorist agents. Better to act on the safe side than to risk grave consequences.

Health and Safety Considerations for Crime Scene Personnel4 Crime scenes present potential safety risks to personnel. An understanding and appreciation of the potential risks coupled with appropriate safety precautions will minimize these risks. The following medical problems are listed as possible biohazards to law enforcement personnel and crime scene investigators. These nonroutine pathogens are not intended to include the “expected” human source blood-borne pathogens (e.g., AIDS and hepatitis viruses). Whenever an investigator has concerns about health symptoms, he or she should seek and obtain professional medical advice. Because it is presented in considerable detail, the following material is perhaps more information than the average reader may wish to review. Anaphylactic shock is a life-threatening allergic reaction that may occur in people with extreme sensitivity to a particular allergen (e.g., insect sting). The reaction occurs most often following a direct injection into the bloodstream that provokes a massive release of histamine and other chemicals. Blood vessels dilate with a sudden loss of blood pressure (symptoms include itchy rash, breathing difﬁculty, and swollen tongue or throat). Severe reaction or collapse requires medical attention. First aid includes raising the legs above the head to improve blood ﬂow to the heart and brain and CPR as appropriate. Individuals who have suffered severe reactions may be prescribed and carry preloaded epinephrine syringes for injection. Hanta virus disease is found in rodent urine, feces, and saliva. Pulmonary syndrome Hanta virus symptoms begin as ordinary ﬂu-like aches and pains and then develop into respiratory distress within 3 days (capillaries begin leaking); over a period of hours patients enter a critical phase in which it becomes progressively more difﬁcult to breathe. Death may result from the loss of blood. Workers in a known area of contamination who develop fever or respiratory problems within 45 days from exposure should immediately seek medical attention and inform their physician of the potential occupational risk of Hanta virus infection. Rodents are the primary vectors although other small mammals can be infected. The deer mouse is the primary reservoir in the southwestern U.S., although serologic evidence of infection has also been found in pinion and brush mice as well as western chipmunks. Respiratory protection with at least a high-efﬁciency particulate air (HEPA) ﬁlter respirator5 is a special precaution for workers (clean-up) in homes of persons

4 This material was largely derived from the California Criminalistics Institute (CCI) and found on their web site located at: http://www.cci.ca.gov/Reference/NonRoutn.pdf. 5 Note that there are speciﬁc OSHA requirements for personnel who use breathing equipment, including HEPA ﬁlter masks.

© 2004 by CRC Press LLC

with conﬁrmed Hanta virus infection or buildings with heavy rodent infestations, and also for persons in affected areas who frequently handle or are exposed to rodents. Lyme disease is caused by a bacterium/spirochete in rodents that is transferred to humans by tick bites. Symptoms include skin changes (red dot gradually expanding), ﬂulike symptoms, and joint inﬂammation. Treatment with antibiotics is more effective during early stages of a disease progression that may include the heart and nervous system. Meningitis is caused by a variety of microorganisms. Viral meningitis is usually not serious and affects up to 12,000 people each year. Meningococcal meningitis is the most common bacterial meningitis, affecting up to 5000 young people (70% under age 5) each year. The meningococcal form is life threatening and needs prompt medical treatment. Symptoms include fever, severe headache, nausea and vomiting, dislike of light, and a stiff neck. Symptoms may develop rapidly over a few hours. A blotchy skin rash develops in about one half of the cases. In severe cases, confusion, delirium, seizures, coma, and shock occur. Although up to 40% of the population are nasopharyngeal carriers, very few develop the disease, which is transmitted by droplets. Patients receiving prompt medical treatment usually recover. Where close household contact (or mouth-to-mouth resuscitation) occurs, prophylactic antimicrobials can be effective. Pneumococcal meningitis is the most common cause of meningitis in adults and second most common cause in children over the age of 6. Plague or the so-called Black Death was responsible for the deaths of 25 million people in the 14th century. Today, spring and summer rodent ﬂea bites cause 10 to 50 cases per year, with the risk of death less than 5% after prompt treatment with antibiotics. A vaccination is available for individuals at high risk. The public health concern is that wild rats will pass the ﬂeas to urban rodents, infecting people when the rat dies and the ﬂeas leave the carcass. Symptoms of bubonic plague include: within 2 to 5 days, fever, shivering and severe headache, followed by “buboes” — smooth, oval, reddened, intensely painful swellings usually in the groin and less commonly in armpits and neck or elsewhere. Bleeding around the buboes leading to dark patches that may occur with occasional blood poisoning. Untreated, the disease is 50% fatal. Pneumonic plague may result as a complication of bubonic plague, causing severe coughing and producing blood, frothy sputum, and labored breathing; this is nearly always fatal unless diagnosed and treated early. The pneumonic plague can pass from person to person by infected droplets expelled during coughing. Poison oak grows as vines or bushes and its leaves have three leaﬂets. The harmful oil resin, called urushiol, is also found in poison ivy and sumac. Touching results in itching, burning, and blistering at the site of contact. The response is not immediate and may occur 24 to 48 hours after contact. People with sensitivity may have extremely severe skin reactions. Prompt ﬁrst aid (within 5 minutes of contact) by washing the affected area with soap and water may avoid a rash; sponging with alcohol is an alternative. After the rash develops, application of calamine lotion may help relieve itching and act as a drying agent. Corticosteroids may be recommended in severe cases (topically for small areas or by mouth if a large area is affected). Scratching or the watery liquid from the blisters does not spread the rash. Pulmonary tuberculosis is caused by Mycobacterium tuberculosis and transmitted from person to person via an aerial route (other routes have been documented but none of major importance). Tubercle bacilli form nuclei for water droplets in respiratory secretions and are expelled during coughing, sneezing, and vocalizing. The moisture evaporates, leaving the desiccated bacilli airborne for long periods. Settled bacilli can absorb moisture

© 2004 by CRC Press LLC

from the environment and remain viable for weeks; they can be thrown back into air currents by walking through the room. Although the number of bacilli excreted is usually not large and household contact for many months is required for disease transmission, some infectious persons may be highly contagious because of the extent of disease (in the respiratory system), which relates to an increased concentration of expelled bacilli and frequency of coughing. Mycobacteria are susceptible to ultraviolet light and disease transmission rarely occurs out of doors in daylight. Increased fresh ventilation is the most important environmental measure to prevent disease transmission. Initial infection is from one to three organisms that reach the deep lungs (alveoli) where they are ingested by scavenger cells in the blood (macrophages) and transported to regional lymph nodes, in which they are destroyed, or pass to the bloodstream, resulting in widespread dissemination. Surviving bacilli inside the macrophages continue to multiply for 2 to 8 weeks until the cellular immune response (T-lymphocytes) is effective in stopping the spread of disease by grouping the infection into nodules (granulomas). Mycobacteria may survive inside the granulomas but be held in check from further spread; the granulomas may calcify and be detectable on chest x-rays. This stage of infection usually does not produce symptoms and is termed primary tuberculosis. The overwhelming majority (90%) of primary tuberculosis cases in the U.S. end at this stage. (95% of the individuals who successfully resolve the primary infection undergo complete healing with no subsequent recurrence.) Progressive primary tuberculosis occurs in the remaining 10% of the infected cases, resulting in a dry cough that at ﬁrst progresses to a productive cough containing sputum, pus, and sometimes blood. Other symptoms include fatigue, weight loss, anorexia, low-grade fever, and night sweats. Untreated, the pulmonary lesions grow and normal pulmonary architecture is lost, resulting in death in about 60% of the cases with a median course to death of 2.5 years. Sometimes the disease reactivates. Reactivation tuberculosis presents similar symptoms as pulmonary tuberculosis and occurs when the immune system is no longer effective in containing the “walled-off ” bacilli. Prevention of tuberculosis (TB) after some types of exposures may be medically indicated with drugs. A number of live TB vaccines are available and known collectively as BCG. However, the efﬁcacy (ability to produce the desired effect) is in question. Controlled studies in North America and the U.K. indicate that vaccination offered greater than 80% protection, while little or no protection developed in other populations. The vaccine is not routinely used in laboratory personnel. BSL 2 precautions are recommended for preparing acid fast smears, while BSL 3 precautions are recommended for propagation and manipulation of cultures or handling nonhuman primates (because they have a respiratory reﬂex like humans and can transmit the disease through the aerial mode). BSL 3 adds respirators to the list of potential personal protective equipment, and the 1988 version of “Biosafety in Microbiological and Biomedical Laboratories” has a special precaution that “molded surgical masks or respirators are worn in rooms containing infected animals.” An article by Neville Tompkins in Occupational Health & Safety, Vol. 62, May, 1993, reports that although some experts disagree, the National Institute for Occupational Safety and Health (NIOSH) recommended in October, 1992, that high-powered air-purifying respirators be worn by health care workers. Reportedly, other major public health and medical organizations including the CDC, American Lung Association, and Infectious Disease Society of America recommend (in part) that “health care workers and others entering TB isolation rooms should wear particulate respirators which resemble surgical

© 2004 by CRC Press LLC

masks, but are far more effective in blocking TB bacteria.” In October, 1993, the CDC recommended ﬁlter characteristics capable of removing particles 1 m in size at 95% efﬁciency. The only ﬁlters that meet that standard today are HEPA ﬁlters that remove particles 0.3 m in size at 99.97% efﬁciency. In May, 1994, NIOSH proposed changes in the respirator certiﬁcation process to test ﬁlters for particles of 0.3 m but at three different efﬁciencies (99.97, 99, and 95%). Rabies is an acute viral disease caused by the transmission of infected secretions, usually saliva, from an infected animal licking damaged skin, mucous membrane, or from a bite. Transmission is also known from infected aerosols, and postexposure prophylaxis is always indicated subsequent to a bite where the bat cannot be sacriﬁced for brain tissue testing (other common reservoirs include skunks, foxes, and raccoons). The virus replicates in muscle tissue near the point of entry and then travels from the wound along nerve pathways to the brain where further replication occurs in the gray matter. The virus then spreads to other tissues and organs via autonomic nerves. Depending on the amount of virus introduced, the host’s immune defenses, and the distance the virus must travel to the brain, incubation varies signiﬁcantly from 10 days to over 1 year (average 4 to 8 weeks). Clinical symptoms include fever, headache, malaise, myalgias (muscular pain), anorexia, nausea, vomiting, sore throat, and an inability to drink water, progressing to marked increase of motor activity, excitation, confusion, hallucinations, combativeness, bizarre aberrations of thought, and increasingly shorter periods of lucid thought until a lapse into coma and ﬁnally death by respiratory failure. Once symptoms start, the disease is almost always fatal, with only three well-documented cases of recovery. Postexposure prophylaxis is effective. Follow-up evaluation from over 575 cases of bites from conﬁrmed rabid animals has shown that no person who has received passive (antirabies antiserum) and active immunization (antirabies vaccine) has developed the disease. In the U.S., fewer than ﬁve rabies cases are reported each year. Rocky Mountain spotted fever is caused by a parasitic microorganism (a type of rickettsia) to arthropods (insect and insect-like animals, e.g., lice, ﬂeas, ticks and mites). Like viruses, rickettsiae can only procreate by invading the cells of another life form. Transfer to humans is by the bite of an infected tick or from its feces where the rickettsiae can pass through a break in the skin to access blood. About 1000 cases are reported per year, mostly on the Atlantic seaboard. Symptoms include anorexia, nausea, and sore throat progressing to fever, aching, and headache in 3 to 10 days. Small pink spots appear on the wrists and ankles 2 to 6 days after symptoms begin, then spread over the body, darken, enlarge, and bleed. Treatment with antibiotics usually cures the disease. Untreated cases marked with high fever may result in death from pneumonia or heart failure. Prevention involves using insect repellent in tick-infested areas, examining the body daily, and gently pulling away ticks with forceps when found. San Joaquin Valley fever is caused by inhalation of a mold that grows in soil; about 60% of infections are subclinical (unrecognized except for a positive coccidioidin skin test). Symptoms may be more severe in other cases requiring medical attention. Fewer that 1% of the cases result in spread of the disease from the chest, or meningeal form, which has signiﬁcant long-term mortality rates. Prognosis in cases where the disease is limited to the chest is good by providing necessary symptomatic therapy. Limited disease symptoms after 10- to 30-day incubation include inﬂuenza-like illness with malaise (vague feeling of illness or depression), fever, backache, headache, and cough.

© 2004 by CRC Press LLC

Scabies or mites, barely visible as white dots, burrow into the skin where they lay eggs and can be seen on the skin as tiny, gray, scaly swellings, usually between ﬁngers, and on wrists, genitals, and armpits. Infestation causes intense itching, especially at night, and scratching results in scabs and sores. Although infestation is most likely through physical contact (e.g., sexual intercourse), scabies is highly contagious and can pass from one person to another standing close to the infested person. Usually the whole family is treated by applying an insecticide lotion to all skin below the head. Snakebite may be predominantly neurotoxic (coral snake) causing respiratory paralysis; or predominantly cytolytic (e.g., rattlesnake) causing local pain, redness, swelling, and forcing the ﬂow of blood out of surrounding tissue. Tingling in the mouth, metallic taste, nausea, and vomiting may occur. Emergency treatment includes immobilizing the patient and part bitten in a horizontal position. Avoid manipulation of the area bitten and immediately transport the patient to a medical facility for treatment. Do not give the victim alcohol or stimulants, or apply ice. The trauma to underlying tissue resulting from incision and suction performed by untrained personnel is probably not justiﬁed, considering less than 10% of the venom can be recovered. Spider bites involve toxins causing localized pain, redness, and swelling and is selflimiting. The more venomous black widow spider causes generalized muscular pains, muscle spasms starting at the site and spreading, and rigidity. Symptoms may continue for several days. Death from cardiac arrest or respiratory failure occurs occasionally in children and the elderly, but is uncommon in adults. Treatment for black widow bites is to relieve symptoms with narcotics or muscle relaxants. Antivenom is usually not required but is used for the very young or elderly who do not respond to the previous treatment. There is no proven treatment for the bite of the brown recluse spider. Its bite may lead to the death of local tissue, requiring excision; other treatments are being developed. Tetanus is caused by spores of a bacteria found in soil and manure (and human intestines); infection produces pain and tingling at the site of inoculation, followed by spastic reaction of nearby muscles. Usually, stiffness of the jaw (“lockjaw”) and neck, dysphagia (difﬁculty swallowing), and irritability follow. Spasms and rigidity of muscles develop in the abdomen, neck, and back. Asphyxia (unconsciousness or death caused by lack of oxygen) may result from spasms in the larynx or chest. Spasms usually subside in 10 to 14 days. The disease is completely preventable by active immunization, beginning with childhood vaccination and obtaining booster doses every 10 years, or at the time of puncture injury (including human bites) if it occurs 5 years after a dose.

Conclusion Because many of the experts with whom investigators must work do not come from police backgrounds, interpersonal skills are vital. Most experts, including those who routinely or only occasionally work for law enforcement, are eager to help. However, police investigators should remember that they are working with people from a variety of backgrounds. Working with them in a spirit of mutual cooperation and respect and in a professional manner will aid in achieving successful outcomes to investigations.

© 2004 by CRC Press LLC

Processing the Crime Scene

5

Chapter 3 brieﬂy outlined some of the measures necessary for a proper crime scene search. The purpose of this chapter is to develop these concepts more thoroughly into a plan for processing a crime scene.

Plan of Action Processing a crime scene, including careful examination, note taking, sketching, photography, and collection of physical evidence, requires a plan of action. The crime scene must be approached in a systematic, methodical way; certain steps must be performed before others. Considerations about legal and scientiﬁc matters must be made when searching a crime scene. These details must be included in an action plan or method of approach and practiced when examining the scene of a crime. The plan of action should be readily available to crime scene investigators. It should be included in a written departmental procedure to deﬁne crime scene responsibilities, and may also detail what tasks are to be done and in what order. It is, of course, impossible to anticipate every detail in a crime scene investigation; however, certain ground rules should be set forth to direct uniformed personnel, detectives, and crime scene investigators to a speciﬁc goal.

Note Taking Of all the duties and responsibilities of an ofﬁcer conducting the crime scene search, perhaps the most important is note taking. Note taking is important for several reasons. It forces investigators to commit observations to writing and to keep a detailed record of everything observed and accomplished. Frequently, a seemingly insigniﬁcant item found in an investigator’s notebook turns out to be critical to an investigation. Some general points about notes and note taking are: 1. Notes should be made as events unfold, and in chronological order. 2. Notes should detail, step-by-step, all actions. 3. Notes should be complete and thorough.

© 2004 by CRC Press LLC

4. Notes should be clearly and legibly written. Sloppy notes or those that do not clearly state the investigator’s meaning will be subject to misinterpretation. 5. Negative or unexpected conditions (the absence of bloodstains or a light that is found on) should be noted. 6. The note taker should be as speciﬁc as possible. If an item of evidence is to be located, a description such as “on the living room ﬂoor, 6 inches east of the west wall and 3 feet south of the north wall” should be used. Vague statements such as “near” or “to the left of ” should be avoided. 7. Case notes, sketches, tape recordings, or photographic negatives should never be discarded. They should be placed into a case folder and retained for as long as the department’s policy indicates. The investigating ofﬁcer or detective is responsible for the entire investigation, including the crime scene. Upon arrival at the scene, the detective should obtain a brief statement from the ﬁrst ofﬁcer at the scene, detailing what transpired. The investigating ofﬁcer should gather much information, and many facts and opinions, from the ﬁrst ofﬁcers. The investigating ofﬁcer’s ﬁrst contact with the scene will be a cursory one. Care should be taken not to disturb anything. Evidence should not be moved or touched. Evidence will be properly documented, measured, sketched, photographed, and ﬁngerprinted later. At the start of the process, the investigator will begin to digest information reported by ﬁrst ofﬁcers, witnesses, victims, and suspects, together with the overall appearance of the crime scene. These details are used to formulate a plan to process the crime scene. Protecting the crime scene is an ongoing concern. Uniformed ofﬁcers should remain posted at the scene. The victim’s family, the public, and the press should be kept away from the crime scene. Fellow ofﬁcers, especially command ofﬁcers, who have no business visiting the crime scene are a more serious problem. In highly publicized crimes, superior ofﬁcers often exhibit a desire to view the scene. This should be avoided; one suggestion is to set up a command post with a pot of coffee to help keep unnecessary persons away. Another possibility to discourage ofﬁcers who visit a scene is to give them an assignment and require them to ﬁle a written report or, at the minimum, have them sign a log. Sometimes it may be necessary for the investigator in charge of the crime scene to inform the superiors politely that the scene is still active and their presence might compromise ﬁndings and interfere with collecting physical evidence. Tape recorders make it easy to take down information that can be transcribed later; some investigators use pocket microcassette tape recorders for note taking. Investigators should remember that impromptu remarks from other ofﬁcers at the scene might later prove embarrassing. Videotaping creates similar problems. Notes taken at crime scenes should include the following information: • • • • • •

Date and time the crime was ﬁrst reported to the police Type of crime Location of the crime scene and a description of the area Description of the crime or event leading up to the investigation Name of the person who requested the crime scene investigation Names of all ofﬁcers, witnesses, investigators, and specialized personnel at the crime scene

© 2004 by CRC Press LLC

• • • • • • • •

Names of the persons who conducted the crime scene search and who took photographs and ﬁngerprints, made sketches, and collected evidence Weather and lighting conditions at the time of the investigation Description of the primary crime scene, including the location of the body and accompanying details Location of any evidence found during the investigation and the names of those who collected it, and the results of a search for ﬁngerprints and other trace evidence Description of the location, including the surrounding houses, streets, and community Description of the interior and exterior of the crime scene, including the type of residence, number of rooms, and windows Description of the outside of the scene including the terrain, type of plants, soil, etc. The date and time the crime scene investigation was concluded

These details represent only some of the many pieces of information that should be included in the investigator’s notes; they do not represent all the possible information. Ofﬁcers should use this list as a guide. Meticulous note taking is one of the keys to good police work and competent crime scene investigation.

Crime Scene Search Once the investigator has gathered as much information as possible and made a survey of the location, the actual crime scene search may begin. Processing a crime scene consists of: 1. 2. 3. 4. 5.

Surveying the crime scene Photographing and sketching the crime scene Mapping and measuring the crime scene Recording and documenting the location of physical evidence at the crime scene Searching for ﬁngerprints and other physical evidence

As a simple, general rule, the most ﬂeeting, fragile evidence should be collected ﬁrst. Thus, taking photographs and making crime scene sketches take priority because crime scenes change with the passage of time and the investigator’s objective is to make a record of the scene that reﬂects as closely as possible its original condition. A systematic search of the crime scene should be conducted. Criminal investigation texts recommend a variety of search patterns: the strip or lane search, grid search, spiral search, and quadrant search. Some search patterns lend themselves to outdoor areas, while others are more appropriate to indoor crime scenes. The important idea to remember is that thoroughness is the goal of the search plan1 (Figure 5.1). Indoor crime scene searches are best done with two persons. One easy way of accomplishing a search in a room is to divide it in half. Each investigator searches one half. After they have done a thorough search, they switch halves.

1

Whatever the search procedure, the “mill around” method is never correct. In this method, using a pen or pencil (for indoor crime scenes) or a stick (for outdoor ones), the ofﬁcer randomly pokes around, pushing aside objects and picking up items that look interesting. This is never a proper way to conduct a search!

© 2004 by CRC Press LLC

Figure 5.1 A workable pattern for conducting a crime scene search should be formulated and used. Several typical patterns are shown here. The speciﬁc case will dictate which search pattern is used.

Outdoor searches often cover greater areas than indoor ones and more searchers may be required. Again, a systematic method should be used. The area can be roped off into grids, each square representing a given search area. A 6- ¥ 6-foot area is a reasonable size for a detailed and comprehensive search. As in the indoor search, each area should be double-checked for thoroughness. Do not forget to look up! Generally, investigators concentrate on what is on the ground and at eye level when searching a crime scene. However, evidence may be above their heads, on ceilings, or caught in tree branches. Before walking onto tile ﬂoors, crime scene investigators should consider that shoe prints might be present in dust or dirt. Even if others have already walked on the ﬂoor, it is worth a try to look for prints. A simple technique is to use a ﬂashlight shined at a low or oblique angle to the ﬂoor in a darkened room to look for dust prints. If any are present, they can be photographed with a camera on a tripod using ﬂash side lighting. After photographs are taken, the print can be lifted using an electrostatic dust print lifter or a large rubber-backed lifter. Both items are commercially available from police supply companies. Nighttime outdoor crime scene searches present difﬁcult problems. If possible, any search should be put off until daylight hours. If waiting is not possible, high-intensity lighting and portable generators may provide sufﬁcient light. Fire departments generally have such gear. Vehicle searches demand the same degree of care. The nature of the crime determines the area of the car to be searched. In hit-and-run cases, the exterior and undercarriage are important; the interior is examined more carefully in a rape or murder case. In most cases, examinations begin with an examination of the exterior portions of the vehicle. In a hitand-run incident, the examination focuses on areas that struck the victim: bumper, grill, windshield, and undercarriage. Look for the presence of dents, broken headlamps, damaged paint, and fabric impressions. Blood, hair, torn pieces of clothing, or ﬁbers may be

© 2004 by CRC Press LLC

present. Broken and missing parts of the vehicle should be thoroughly documented. A hydraulic lift can be used to lift the car to examine the undercarriage for evidence. All evidence should be photographed and sketched. Fingerprints may be found on door handles, outside mirrors, or the area above the driver’s-side exterior door panel where some drivers rest their left hands. The interior of the vehicle should be searched for ﬁngerprints. A systematic approach should be taken, such as dividing the interior into sections: front right, front left, and back right, back left. Before entering the vehicle, an examination for trace evidence should be made. If anything of value is noted or suspected, it should be collected before entering the car. Trace evidence such as hairs and ﬁbers can be collected using forceps or tape lifts. Vacuum cleaners can be used; however, vacuums pick up much debris, which causes considerable extra work for laboratory examiners. Considering the possibility of ﬁnding trace evidence will cause the investigator to avoid contaminating the interior of the vehicle with foreign material that may be carried inside by the examiner. Fingerprints should be searched for after trace evidence is collected (Figure 5.3).

Crime Scene Photography The well-worn saying “one picture is worth a thousand words” certainly holds true with crime scene photography. No matter how well an investigator can verbally describe a crime scene, photographs can tell the same story better and more easily. The following is not intended to make the reader an expert in photography, but merely to discuss certain issues that relate to photography in general and crime scene photography in particular. Before a detailed examination of the crime scene is made or before any items are moved or even touched, the crime scene should be photographed. The photographs should be taken to clearly and accurately depict the scene as it was found, the paths taken by the criminal to the scene, the point of entry, the exit, and the escape route. Detailed photographs should be taken to show items of physical evidence in the condition in which they were found by the investigator prior to their removal. Types of Cameras Many types of cameras are available for use in crime scene photography. Larger format cameras, such as a 4 ¥ 5 or 120 were the trend in past years, favored because they produced a larger negative that resulted in more clarity when enlarging photographs. If two identical scenes are photographed with a 4 ¥ 5 camera and a 35-mm camera with the same type of ﬁlm and enlargements are made from each, the photograph taken with the larger format camera offers greater resolution, and very small objects will be easier to pick out. Not withstanding the beneﬁts of the large-format camera, 35-mm cameras have become the norm. The 35-mm single-lens reﬂex camera offers the greatest versatility. Many police departments choose this camera for routine crime scene work when issues such as cost of ﬁlm and camera and ease of use are considered. So-called “point and shoot” cameras are useful in a variety of instances. They are inexpensive, take acceptable pictures, and are useful for ofﬁcers who do not have much training in photography. The cost of these cameras and the even more inexpensive “disposable” cameras makes it possible for every police vehicle to carry a camera for use as needed.

© 2004 by CRC Press LLC

Figure 5.2 (A) Crime scene investigator lifting a foil ﬁlm to collect a footprint using static electricity. (B) The lift is shown next to a photograph of the shoe’s sole. (Zurich Cantonal Police Forensic Science Laboratory.)

© 2004 by CRC Press LLC

Figure 5.3 The vinyl seat of a car with distinctive gang-style writing (the “187” refers to the California Penal Code section for murder). (Los Angeles County Sheriff’s Department.)

Polaroid“ cameras are useful for identiﬁcation photographs. If a photograph of a deceased person is needed to identify him, a Polaroid photograph works well. The quality of the photos is acceptable. However, cost is a consideration. Police agencies may wish to limit the number of Polaroid cameras available for ﬁeld use because ﬁlm costs can mount rapidly. Digital cameras represent the latest technology and deserve consideration. During the last few years prices have fallen and quality has improved, making digital photography a cost-effective choice. Instead of ﬁlm, photographic images are stored on magnetic devices. The diskettes can be placed into a computer and viewed on the screen and printed out using a specialized printer. Pictures can also be incorporated into a report. The cost of digital cameras is at the point at which they are comparable to 35-mm cameras and have near-comparable resolution. Digital photography is a rapidly evolving technology that will see greater use and ultimately eclipse traditional photography. Types of Media Numerous types of ﬁlm are available today. Color negative ﬁlm has become standard in many police departments. Print ﬁlm speeds are available as high as ASA 1600 for color and ASA 3200 for black and white (which can actually be pushed to an ASA of 5000). Color photography offers good color rendition and presents few problems in indoor or outdoor crime scenes. Black and white ﬁlm should not be dismissed. It is less expensive than color ﬁlm and offers excellent resolution and very high speed when needed in very low light and near-dark situations. For digital cameras, the photographic resolution is measured in pixels. Camera prices increase with increased resolution. For crime scene photography, a digital camera with a

© 2004 by CRC Press LLC

resolution of 4 megapixels is the lowest resolution one should consider. A 4-megapixel camera will yield a reasonably clear 8 ¥ 10 inch photograph; however, for photos requiring greater resolution, traditional ﬁlm cameras are preferred. Number of Photographs How many photographs should be taken? There is no simple answer, but as a general rule, it is better to overshoot a crime scene (take more photographs than are necessary) than to economize and take too few. Time, however, may be a concern. Certain types of evidence need to be collected quickly. In the ﬁnal analysis, the experience of the crime scene photographer can best answer the question of the number of photos to take. Photographs serve a number of purposes. They aid in refreshing the memories of witnesses and investigators and show the relationships of items of evidence at the crime scene. A very important purpose of crime scene photographs is that they help to convey an image of the crime scene and the circumstances of the crime to the jury. With these purposes in mind, a number of important photographs should be made in almost every crime scene, including (Figure 5.4): •

•

•

•

Location. Photographs of the location of the crime scene should be made. In the case of a residence, for example, the exterior of the dwelling should be shot, including the locations of doors and windows. Photographs of surrounding areas of the house should be included, such as the front and backyards and views in each direction. Aerial photographs are often useful to depict the location of the principal site and other areas of interest in proximity to the crime scene. Witness photographs. Witness photographs are overall photos of the crime scene. They depict the scene as observed by a witness. In the case of a murder crime scene in a house, such photographs might depict the victim lying on the ﬂoor as viewed from a number of locations in the room. These photographs are designed to tell a story, to relate what the location looked like to someone who was not present. To accomplish this task, several overlapping photographs should be made. In addition, long- and intermediate-range photographs should be taken to show perspective and the relative positions of different items found at the crime scene. Close-up photographs. In addition to long- and intermediate-range photos, closeup pictures should also be taken to further clarify the scene. Two photographs should be routinely taken: (1) one showing the item as it actually appears and (2) a photograph of the same item with a ruler included. It is important that the ﬁlm plane be parallel to the plane of the object. The ruler and the parallel ﬁlm plane ensure the ability later to produce good-quality enlargements or 1:1 photographs of the evidence. Evidence photographs. Photographs of all items of evidence should be made prior to their removal or changing the location or position of items in any way. Photographs should be made of shoe imprints, ﬁngerprints, bloodstains, weapons, defense wounds, and other such items. Additional photographs should be taken during the crime scene search as new items of evidence are discovered when items at the crime scene are moved.

When taking photographs, a photo log is recommended. Some police agencies use preprinted forms and others keep track of photographs by some other means. A typical

© 2004 by CRC Press LLC

Figure 5.4 Photographs of a crime scene serve to depict its nature and extent. Photograph (A) is a view from one perspective; the aerial view (B) provides a picture of the total scene. (Los Angeles County Sheriff’s Department.)

© 2004 by CRC Press LLC

Figure 5.5 A bearded victim was shot in the face with a shotgun. A small fragment of beard hair and skin spattered back onto the suspect’s corduroy coat. (Los Angeles County Sheriff’s Department.)

log might include the case number, date, time, photographer’s name, type of camera, lens, ﬁlm, and a listing of each photograph. The list may include the shutter speed, f-stop, and a very brief description of the location of the evidence. An alternative to a photo log is using a camera back that automatically places the date onto the photograph. Normally, photographs should be taken at eye level to give the proper perspective of the scene. If the photo is taken from a different perspective, it should be noted in the log. The type of lens used also affects the perspective of the scene. A normal lens should be used, such as a 50-mm lens in the 35-mm format. If the crime scene is indoors with cramped quarters, medium-wide-angle lenses may be used; however, the lens change should be noted in the photo log. In low-light situations, ﬂash photography is recommended even though high-speed ﬁlm may handle these situations. Most shooting is done with a hand-held camera, but for exposures less than 1/60th of a second, a tripod should be used to ensure sharp photographs. Photographs accurately represent the crime scene as seen by the witness or investigator. They should be clear and sharp. Extraneous subjects and items at the scene do not belong in the photographs; crime scene equipment and personnel should not be present in photographs. Posed photographs that locate where a witness stood when ﬁrst entering the crime scene may be taken. A photograph should then be taken from that location to show the appearance of the crime scene from that point of observation. This section is not meant to be an all-encompassing guide to crime scene photography, but rather to present some important points to consider. Several worthwhile classes in general photography that give the beginning crime scene photographer the basics on the

© 2004 by CRC Press LLC

Figure 5.6 These playing cards (left) look perfectly normal under ordinary room light. They are, however, obviously marked (right), as shown when viewed and photographed under reﬂective infrared lighting. (Los Angeles County Sheriff’s Department.)

subject of photography are offered in colleges and adult education programs. The Kodak Master Film Guide, available in most photography shops, is a valuable pocket reference that can be carried in a ﬁeld kit for ready information. Nikon offers a good photography school on basic 35-mm photography at locations around the country; this is an excellent program for individuals reasonably familiar with general photography who wish to improve their capabilities. Universities and junior colleges with police science programs may offer classes on crime scene photography. Professional organizations like the International Association for Identiﬁcation have presentations on crime scene photography from time to time at annual seminars. Admissibility of Photographs For a photograph to be admissible in court, the investigator must be able to testify that it accurately depicts the area shown. To be accurate, it must represent the subject matter properly in terms of color, scale, and form. Photographs must be in focus and should show the relationships and distances between objects. Crime scene sketches (discussed later) also assist in depicting the crime scene. All negatives from the crime scene photographs should be retained. They are important to demonstrate that the picture has not been altered. Negatives are also important if enlargements of certain areas of the crime scene are needed to better depict parts of a photograph.

© 2004 by CRC Press LLC

To reiterate the importance of scales or rulers in photographs: they are essential to show the actual size of the object in question. Some courts may not allow even minor modiﬁcations of photographs; in those cases, it may be necessary to take duplicate photographs to show the scene (1) as it was and (2) with the scale. Videotape Another method of recording the crime scene is videotape. Lightweight, portable, lowlight video cameras are ideally suited for gathering a video rendition of a crime scene. Videography does not do away with the need for still crime-scene photographs, but has the advantage of more graphically depicting the scene. When videotaping a scene, the investigator should walk the video operator through the location. The ﬁlming should begin outside an indoor crime scene or with an overall pan of the outdoor location. The detective should narrate the videotape by recording the audio portion as the videotape is shot. The narration should include the name of the speaker, time, date, location, case number, and other pertinent identifying information. If videotapes are to be used as evidence, they should not be edited or erased. The entire tape must be in its original condition if it is to be admissible as evidence. Some agencies use edited videos solely to refresh the investigator’s memory. Courts may or may not admit these tapes for the jury’s consideration. As with most generalizations on the legal aspects of crime scenes, it is prudent to check with local authorities to determine what will be acceptable to the prosecution and to the court. It is better to ﬁnd out in advance rather than to assume the practice is acceptable and then ﬁnd out that a key piece of evidence is excluded for some legal reason not considered by the investigator. While the scene is being recorded, other personnel at the location should be silent because their voices can be picked up. Such conversations may prove distracting and sometimes embarrassing if recorded. As with photographs, close-up videotape recordings of small items of evidence should contain a scale to show the actual size of the item. Additionally, panning the area and zooming in on the item should show the relative location.

Sketching the Crime Scene Photographs alone are not sufﬁcient for recording a crime scene adequately. A crime scene sketch should also be routinely made. Sketches and photographs complement each other to depict the crime scene adequately and properly. Sketches clarify the appearance of the crime scene and make it easier to comprehend. It is, therefore, important for investigators to develop the ability to make good crime scene sketches. A crime scene sketch is not considered an architectural drawing, such as one drawn by an artist or forensic surveyor. It is simply an illustrative diagram or drawing that accurately depicts the appearance of the crime scene. Nevertheless, sketching the crime scene requires some skill on the part of the investigator. Generally, it is easier if two people work on the sketch: one person to draw and the other to take measurements. Sketches sometimes leave out important information or contain errors. Yet despite these drawbacks to and problems in making crime scene sketches, they do provide important information and, when done properly, are very helpful. Sketches help investigators

© 2004 by CRC Press LLC

recall details of the crime scene. They also aid prosecutors, courts, and juries to better understand the crime scene. Sketches offer a permanent record of the relationship of items at the scene to each other and help to supplement photographs. They depict the overall layout of the location more easily than can be accomplished by photographs. Sketches also allow for selectivity. A sketch may be drawn purposely to leave out extraneous or confusing details that would be recorded in a photograph. Crime scene sketches can provide a record of conditions that are not readily recorded by other means. Distances can be shown over large areas and topography can be easily illustrated. Paths taken by subjects or vehicles can be demonstrated on drawings more easily than on photographs. Drawings may be used to aid in questioning suspects and witnesses of crimes and to authenticate testimony of witnesses. Sketches combine the best features of photographs and crime scene notes. Information Included in Crime Scene Sketches What information should be present on a sketch? Information placed on a sketch is used to make the drawing understandable and admissible into evidence. Like all evidence, it should contain case-identifying information: case number, name of suspect, victim, and investigator, person drawing the diagram, and date and time the sketch was made. It should contain a scale, if required, and distance measurements between items present on the sketch. The location depicted in the drawing should be included as well as reference points to located items. A legend or key may be helpful to identify and clarify portions of the drawing. Equipment Writing materials are, of course, required. Although pens may be used, lead pencils are easier to work with, especially if erasures are made. Colored pencils are also useful to outline important items. Graph paper is best to use, although blank paper will do. Graph paper simpliﬁes scale drawings and provides guidelines for line measurements. Some sort of drawing surface, such as a clipboard, is helpful. Measuring devices such as rulers and tapes are required. A 50- or 100-foot surveyor’s tape is especially useful to measure longer distances. A folding 6-foot carpenter’s ruler is also a useful piece of measuring equipment. Inexpensive, infrared-measuring devices used by realtors and contractors make measuring interiors very easy. Finally, a compass is useful to determine the direction. Types of Sketches Different types of indoor and outdoor crime scene locations present different problems in sketching. To best represent the crime scene, it may be necessary to rely upon different types of sketches. The type of sketch chosen by an investigator is not especially important. What is important is that the resulting drawing best depicts the crime scene and most easily illustrates the event to the viewer. The overview, ﬂoor plan, or bird’s-eye-view sketch is the simplest and most common one used in diagramming crime scenes. It may be used in nearly all crime scene situations where the items of interest are located in one plane. In addition to its simplicity, it is also the easiest for laypeople, such as jury members, to grasp.

© 2004 by CRC Press LLC

Another type of crime scene sketch is the elevation drawing. This type of sketch is used when the vertical, rather than the horizontal, plane is of interest. Thus, if bloodstains were present on a wall of a house, the elevation drawing of the wall would be used to depict this scene. The cross-projection, or exploded, view is a combination of the preceding two types. It is similar to the ﬂoor plan sketch except the walls have been folded down into the same plane as the ﬂoor. The perspective drawing is another type of sketch that depicts a three-dimensional drawing of the scene. Although the ﬁnal drawing will be very clear if done properly, this type of sketch requires considerable artistic skill and, therefore, is generally not recommended. Locating Objects in the Sketch Once the drawing has been made and the relative locations of the items have been sketched in, it is necessary to locate them in the sketch. Location is deﬁned as the actual position where the object is located in the crime scene. A position on a plane or ﬂat surface is deﬁned by two measurements. A knife located on the ﬂoor of a room requires two measurements from two ﬁxed points to locate its position on the ﬂoor accurately. A measurement to show location could be taken from the north wall and the east wall, e.g., 3 feet from the north wall and 6 feet 7 inches from the east wall. Although perpendicular measurements are the easiest to use, they may be impossible in outdoor crime scenes. In those situations it is necessary to ﬁnd ﬁxed points to locate the item in question. This can be done by using telephone poles, ﬁre hydrants, trees, the exterior corner of a building, and so on. Whatever the item of reference used, it must be permanent and identiﬁable. The number on a telephone pole, a street address, or a roadside marker may be used as a point of reference to locate an object. GPS, or geopositional satellite devices, are used in a variety of industries and, as costs decrease, are likely to become useful locating the position of evidence in remote outdoor crime scenes. Computer Programs Commercial computer software is available to render drawings of crime scenes in twoand three-dimensional views. In addition to the ability to draw crime scenes to scale, computer programs have been used to depict trajectories in shooting scenes and to help reconstruct crime scenes. Some of the programs are able to depict the scene in three dimensions on a video monitor and take a viewer through the scene by means of computer graphics. In the courtroom, these systems have been used to project the video image onto a screen and explain to a jury the sequence of events in a crime scene. Software can be used to depict the crime scene in pictorial form as seen from the perspective of the victim or the suspect (Figure 5.7). Admissibility of Sketches As with photographs, the sketch may be entered into evidence only by someone competent to testify about its authenticity. The qualiﬁed individual must be able to testify that the sketch is a true and accurate representation of the original scene.

© 2004 by CRC Press LLC

Crime scene diagrams are extremely useful in court presentations. In major crime cases the original crime scene sketch is used frequently as the basis for a ﬁnished drawing made by an artist or by using a computer program. In some instances where the scene is particularly complex, an architectural model may prove useful to detail the crime scene.

Collection of Evidence Following the initial crime scene search, photography, and sketching of the crime scene, physical evidence may be collected. It is useful to set priorities of which evidence to collect ﬁrst. The most fragile evidence, such as ﬁngerprints, should have ﬁrst priority. After ﬁngerprints, other fragile evidence such as blood and trace evidence is collected. Once this has been accomplished, the scene should be searched a second time to make certain that potential evidence was not overlooked. Evidence that is to be sent to the crime laboratory should be packaged to prevent breakage, spoilage, or contamination that will destroy its value. Evidence containers should be sealed and be strong enough so that they will not break in transit. When evidence consists of several objects, they should be packaged in separate containers or wrapped individually. Each package should be clearly marked as to its contents and then packed in a shipping container. Sometimes, it is necessary to ﬁx articles to the shipping container separately so that they will not come in contact with each other. Bottles and glass containers containing liquid should not be packaged with other evidence because they may break and contaminate the other exhibits. If Styrofoam or other packing material is used for cushioning, any objects that might be altered by contact with such packing material should be separated and tightly wrapped. Even if objects have been individually identiﬁed, they should also be marked with the recovering ofﬁcer’s initials and the date collected so that the identity of a given object cannot be questioned. Identiﬁcation markings may be placed directly on the object or on a tag attached directly to the object. When this is not practical, markings are placed onto the sealed container housing the evidence. A transmittal letter with a complete inventory of all items submitted and a request for laboratory examinations should be included with each shipment. The inventory enables lab personnel to check the contents so that small objects among the many items are not misplaced or overlooked. The request for speciﬁc examinations allows the forensic science laboratory to determine what needs to be done. The written request to the laboratory about the case should be as complete as possible, listing sequence of events, statements of the suspect, the victim, witnesses, etc. This information assists the examiner’s evaluation of which laboratory tests are required. The information may also provide answers to questions that come up as a result of the laboratory’s ﬁndings or provide conﬁrmation of ﬁndings that necessarily went beyond those speciﬁcally requested. It may be helpful to include copies of pertinent police reports or interrogations. The following is a brief description of packaging instructions for certain items of evidence: •

Objects with ﬁngerprints or glove prints should be packed so that they do not come in contact with each other or the package sides.

© 2004 by CRC Press LLC

Figure 5.7 (A color version of part A of this ﬁgure follows page 256.) Indoor (A) and outdoor (B) crime scene diagrams using a computer-aided design (CAD) software program. The outdoor scene also has a digital photograph imported into the drawing. (Los Angeles County Sheriff’s Department.)

•

•

• • •

Tool marks on objects should be protected from contamination and moisture. Marks may be protected from rust by a light ﬁlm of oil if transfer of trace material is not indicated. Clothing containing dry biological stains (blood, semen, or saliva) should be wrapped separately and in such a way that the stains are not broken or rubbed off. The stained part of the garment may be attached to a piece of cardboard that is then ﬁxed to the bottom of a cardboard container. If several garments are submitted, they may be ﬁxed separately in compartments built inside the container. The victim’s clothing must not be packaged or come in contact with the suspect’s. Strands of hair on garments should not be allowed to come in contact with other garments that may contain hair. Firearms should be rigidly ﬁxed inside a container without further wrapping. Postal regulations should be consulted before mailing ﬁrearms.

© 2004 by CRC Press LLC

(B)

Figure 5.7 (continued)

• • •

• •

Cartridge cases and bullets should be packed separately with soft cushioning material. Federal regulations should be consulted before shipping. Live cartridges and explosives should be packed in cushioning material to protect ﬁngerprints and shipped by a parcel carrier. Stomach contents and organs for toxicological examination should be placed in tightly sealed glass jars and packed in cushioning material. The containers should be of a size proportionate to the amount of ﬂuid so that volatile agents do not evaporate. Controlled substances should be tightly cushioned in vials or pillboxes so that they will not break. Absorbent cotton should be used. Charred paper should be packed in sturdy boxes and supported on all sides with absorbent cotton. The container should preferably not be shipped, but handcarried to the laboratory. It is also possible to place the charred paper in a large plastic bag that is inﬂated and sealed tightly.

Proper packaging of evidence cannot be overemphasized.

© 2004 by CRC Press LLC

Figure 5.8 Occasionally, a criminal leaves behind an item that at ﬁrst glance may not seem important to the case. This ﬂashlight (A) was left at a murder scene. Fingerprints developed on one of the batteries (B) led to the arrest of a suspect in the case. (Los Angeles County Sheriff’s Department.)

Figure 5.9 Commercially available evidence boxes for a riﬂe, pistol, and knife make collecting such items simple. The boxes also help to preserve items of trace evidence adhering to the larger items. (EVI-PAQ, http://www.evipaq.com.)

© 2004 by CRC Press LLC

Establishing Identity

6

One of the most important purposes of physical evidence is to establish the identity of the suspect or victim. This identiﬁcation is possible through a variety of methods discussed in this chapter. Fingerprints are usually thought of ﬁrst when considering methods of identifying individuals.1 However, techniques such as handwriting examination, forensic anthropology, and forensic odontology are also important and will be discussed.

Fingerprints and Palm Prints Some of the most valuable clues at the crime scene are ﬁnger and palm prints (bare footprints are sometimes discovered and may also identify a person, provided there are known exemplars). Prints are conclusive evidence. An expert’s report may state three possible ﬁndings: • • •

The subject made the print. The subject could not have made the print. The print had insufﬁcient detail to be evaluated.

The value of ﬁngerprints is greatly enhanced by the possibility of identifying a criminal through searching a single ﬁngerprint ﬁle or AFIS, an automated ﬁngerprint identiﬁcation system. In this section, the term “ﬁngerprints” includes all types of prints of friction ridge skin. Prints of the palms or soles of the foot are made under the same conditions as ﬁngerprints and are preserved in the same manner. It is sometimes difﬁcult to decide whether a print has been left by a ﬁnger, the palm, or the sole of a foot. For this reason, in ordinary speech, the term ﬁngerprint has come to include prints of the palms or feet also. How Do Fingerprints Occur? When criminals work, they cannot avoid leaving clues in the form of ﬁngerprints unless they wear gloves or some other form of protection. Prints are formed by friction ridges, 1

Forensic science professional organizations play an important role for practitioners who need to stay current in new technologies. The premier association dealing with forensic identiﬁcation, e.g., ﬁngerprints, is the International Association for Identiﬁcation. Anyone seriously engaged in the ﬁeld of forensic identiﬁcation should consider membership in the IAI as well as state divisions of the IAI.

© 2004 by CRC Press LLC

which deposit grease and perspiration on the object touched, and may be produced when criminals take hold of an object or support themselves with their hands. Prints may be formed when ﬁngers are contaminated with foreign material, such as dirt, blood, or grease, or when the ﬁngers are pressed against a plastic material and produce a negative impression of the pattern of the friction ridges.

Where to Look for Fingerprints In burglary investigations, the perpetrator’s point of entry should be the place at which to start a search for prints. It may be possible at that point to determine if the burglar worked with gloves or uncovered hands. If a door was broken open, prints (including shoe prints) may be located on the lock, the immediate surroundings, or other places on the door where the entry had been forced. With broken windows, particular attention should be given to search for pieces of broken glass, which are useful for standards and may contain prints or blood. The common method to break a window is to knock a small hole in a windowpane. A burglar can then break away pieces of glass with his ﬁngers until he has succeeded in making an opening large enough to be able to reach the window latch. Often, ﬁngerprints or glove prints are found on broken pieces of glass. Broken glass does not always lie just inside the window because burglars sometimes dispose of the broken glass shards to conceal the entry. Fingerprints may be left on the inside of the windowsill, the window frame, and jamb when the burglar climbs through the window and grips these parts of the window frame. Searches for ﬁngerprints should be made in areas where the burglar is suspected to have eaten or had a drink. Prints on glass or china are generally of good quality. If the criminal became drunk at the scene, productive results can be expected from the print search. In some cases the burglar wore gloves at the start, began drinking alcohol, and gradually became intoxicated. Forgetting caution, the gloves were removed. If the burglar removed liquor bottles from the scene, prints may be found on glasses or china or on bottles that were moved and examined by the thief. Light switches, circuit breakers, and fuses should always be examined, as well as any light bulbs that were loosened or removed. If the criminal wore gloves, special care should be taken at places where the activity was of a type in which gloves would have been a hindrance. For example, opening a case or drawers with difﬁcult locks or searching in the drawers of a bureau may be difﬁcult with gloves. Burglars will remove gloves during the crime and leave ﬁngerprints at the scene. If the thief used the toilet, he might have removed his gloves. Prints should be searched for on the toilet-ﬂush lever, on the door lock, and on any paper that may have been used. Burglars sometimes bring tools or other objects to the scene and leave them behind. Fingerprints may be detected on papers used to wrap tools, on ﬂashlights (do not forget to examine the batteries), and other items such as the inside of latex gloves. All smooth surfaces on which prints could have been left should be examined. Good prints are often found on glass, china, polished, painted, or otherwise smooth surfaces, smooth cardboard cartons and paper. In some cases, prints have been recovered on rough surfaces, starched collars, cuffs, and newspapers. When examining furniture, do not omit places the criminal may have touched when pulling out drawers or moving the furniture. Even if the thief

© 2004 by CRC Press LLC

Figure 6.1 The suspect entered a convenience store in Kodiak, Alaska, where he robbed the clerk, hit her in the head with a gun, and forced her into a back room, where he tied her up with an electrical extension cord and attempted to rape her. The police developed a good suspect, but the clerk was unable to identify him. Inked ﬁnger and palm prints were submitted and identiﬁcation was made from the latent prints developed on the plug (A and B) of the extension cord. (Alaska Department of Public Safety, Scientiﬁc Crime Detection Laboratory, Latent Print Section.)

worked with gloved hands, prints may have been left when a heavy piece of furniture was moved because the gloves may have slipped and a part of the wrist or palm left a print. A ﬂashlight is an excellent tool to search for prints. Fingerprints can frequently be seen by holding the ﬂashlight at low angles so that the surface is observed under oblique lighting.

© 2004 by CRC Press LLC

Figure 6.2 (A color version of this ﬁgure follows page 256.) Using a personal workstation with a ductless fume hood is an effective means to reduce the amount of ﬁngerprint powder in the workplace. (Los Angeles County Sheriff’s Department.)

However, ﬂashlights may not work on all surfaces. If prints are expected in a particular place and they are not discovered, the area must be examined by special methods described under the heading “Development of Latent Fingerprints.” During the search for prints, investigators should only wear gloves if blood is present. Investigators should become accustomed to working in a way in which they do not leave their own prints. If an ofﬁcer should accidentally deposit ﬁngerprints, this fact should be recorded so that he or she may later be eliminated from the relevant prints. All prints at the scene of a crime should be preserved, even if they are assumed to belong to the residents.

© 2004 by CRC Press LLC

Figure 6.3 A plastic ﬁngerprint in putty is sometimes found at burglary crime scenes. (Los Angeles County Sheriff’s Department.)

Different Types of Fingerprints Fingerprints can be divided into three main groups: (1) plastic ﬁngerprints, (2) prints of ﬁngers contaminated with some foreign matter or “visible prints,” and (3) latent ﬁngerprints. •

•

•

Plastic ﬁngerprints occur when a ﬁnger touches or presses against plastic material and creates a negative impression of its friction ridge pattern. These prints are found on such materials as fresh paint, on substances that melt easily or soften when held in the hand (e.g., chocolate), on adhesive tape, in thick layers of dust, plastic explosives, putty that has not hardened, candle wax, sealing wax, fats, ﬂour, soap, thick and sticky oily ﬁlms, grease, pitch, tar, resin, and clay, to name a few (Figure 6.3). Prints from ﬁngers contaminated with foreign matter are common. Dust prints occur when a ﬁnger is pressed in a thin layer of dust and some of the dust sticks on the friction ridges. When the ﬁnger is then placed on a clean surface, a ﬁngerprint results. In some cases a dust print may be fully identiﬁable and may be clear enough to search in a single ﬁngerprint ﬁle. Prints can be left when ﬁngers are contaminated with other substances like pigments, ink, soot, ﬂour, face powder, oils, safe insulation, or blood. Latent ﬁngerprints result from small amounts of grease, sweat, and dirt deposited on a surface. Skin on the hands and soles of the feet has no oil glands. Grease found on ﬁngers comes from other parts of the body that the hands touched. Secretion from friction skin contains 98.5 to 99.5% water; the balance is organic and inorganic components. If the hands are cold, practically no liquid is secreted; when they become warm, secretion returns to normal. Latent prints are most often found

© 2004 by CRC Press LLC

on objects with polished or smooth surfaces and on paper. However, under some conditions they may also be detected on rough surfaces, and even on smooth fabrics. “Latent prints” include those invisible to the unaided eye plus all others that are visible but only properly examined after development. Fingerprint Developing Techniques Many advances in ﬁngerprint technology have occurred, such as techniques developed for visualizing prints. Most of these techniques involve chemical reagents that react with materials present in the components that make up the print or contaminants. Collaboration between forensic chemists and forensic identiﬁcation specialists has made these techniques possible and continued effort is to be encouraged. Forensic chemists and criminalists should be assigned to identiﬁcation units within laboratories to work with ﬁngerprint and identiﬁcation specialists to develop and use chemical-based ﬁngerprint visualization techniques. Many procedures are available to develop latent ﬁngerprints. 2 Those listed in the next sections are some of the standard procedures in use; however, new ones are developed regularly. It is important to understand that practical experience with these procedures is needed to use them effectively. Certain of the methods work better than others do for different materials. The sequence of using these procedures is also important because it is possible to use multiple procedures, one following the other, to search for prints. Some procedures have an adverse effect on other types of evidence, e.g., certain solvents can cause inks to run on documents or render biological evidence unsuitable for typing. Latent ﬁngerprint examiners are cautioned that they should understand these techniques before trying them on casework. Latent print examiners should work closely with forensic scientists to develop procedures for using chemical developing methods with safeguards to avoid destruction of other types of physical evidence. Latent print examiners should consider forming regional user groups to help keep up with rapidly changing technology. Such groups are made up of local practitioners who meet monthly and share technical experiences with other practitioners. These regional groups are especially helpful in small identiﬁcation sections with only one or two examiners, who may be unable to attend technical conferences. Development with Powders Brushing ﬁngerprint powder over a latent print makes the print visible. The substances that form the print show up and the print becomes fully visible. The choice of powder depends partly on the kind of surface on which the print is found and partly on how it is to be preserved. If the latent print is of high quality, the choice of material for development is not especially important. Several types of ﬁngerprint powders are commercially available: black, white, colored, aluminum, copper, ﬂuorescent, and magnetic. The type used is determined by the color of the background and the nature of the surface (for example, magnetic powder cannot be used on ferrous materials). There is little safety information about ﬁngerprint powder; however, common sense suggests that long-term exposure to ﬁne particulate matter may cause respiratory problems 2

The FBI has published an excellent reference work, Processing Guide of Developing Latent Prints, Revised 2000, available on its web page for download at: http://www.fbi.gov/hq/lab/fsc/backissu/jan2001/index.htm.

© 2004 by CRC Press LLC

over time. Persons who routinely use ﬁngerprint powders can wear dust masks or specially designed ﬁngerprint hoods to minimize the amount of powder breathed (Figure 6.2). Fiberglass, animal hair, and synthetic or natural ﬁber brushes may be used to develop ﬁngerprints. If the brush is damp or oily, it is useless. The brush is ﬁrst lightly dipped in the powder and then tapped with the ﬁnger so that only a small amount of the powder is left on the brush. The object is then lightly brushed in curved strokes. Powder particles will adhere to all places where there is grease or dirt. If ﬁngerprints are present on the object, they show up more or less clearly. Powder should not be sprinkled over or tapped onto the object while brushing. Prints from sweaty or dirty ﬁngers or produced by a ﬁrm grip may cause the friction ridges to spread out, ﬁlling up the spaces between the ridges. Too much powder can destroy these prints. If too much powder is used, it can be “washed” by pressing a ﬁngerprint lifter against the print. The lifter will remove the excess and the spaces between the ridges may be nearly free of powder. If necessary, the latent print can be reprocessed to get usable results. Some ﬁngerprint examiners use black ﬁngerprint powder as a universal developer on smooth nonporous surfaces. On dark surfaces, such as furniture and ﬁrearms, aluminum or copper powders give good results. These powders are useful if the print is to be photographed before being lifted. Remember: aluminum-powdered lifts appear reversed from prints developed with black powder. Perspiration and grease from ﬁngerprints absorb into porous surfaces such as paper and cardboard, and do not usually give results with powdering methods. On porous items, another method should be used, such as iodine, ninhydrin or silver nitrate treatment. Another

Figure 6.4 Magnetic ﬁngerprint powders work well on some items. Only the rays of powder come in contact with the surface, as in this example on a plastic bag. (Los Angeles County Sheriff’s Department.)

© 2004 by CRC Press LLC

aid to ﬁngerprint development, the Magna-Brush“, utilizes magnetic powders and a magnetic applicator. Streamers of magnetized powder are brought in contact with the suspected surface. Powder adheres to the latent print, while the magnet removes the excess. This method has the advantage of not leaving excess powder on the object and the surrounding area. Because of the nature of the process, it can be used effectively only on nonmagnetic surfaces (Figure 6.4). Fluorescent powders are yet another type that may be used in some special cases. Available in powder and aerosol forms, these powders are used to dust paper currency and documents and sprayed in areas where recurring thefts take place. They are technically not ﬁngerprint powders because they are used prior to the prints being deposited. After the suspect has handled the money or touched the dusted area, the area is examined with ultraviolet light. The latent ﬁngerprint is easily visualized by UV light and may be photographed using proper photographic techniques. Amido Black. This stain turns proteins present in blood blue-black. It does not react with any of the normal components of ﬁngerprints and should be used in conjunction with other developing techniques. Other more sensitive stains such as Coomassie blue, a general protein stain used in forensic biology, may be considered. Fingerprint specialists should always consult forensic biologists before using any protein stains on bloody ﬁngerprints because some stains may cause difﬁculties in blood testing. DFO (1,8-diazaﬂuoren-9-one). DFO is a ninhydrin-like analogue. It reacts with proteins to give a highly ﬂuorescent, red-colored product that is more sensitive than ninhydrin. Although some prints developed using DFO will be visible to the naked eye, illumination with high-intensity light improves the sensitivity; however, interference may become a problem from certain colored inks and papers that ﬂuoresce. Longer wavelength light sources, such as mercury vapor lamps at 546 nm lessen the interference. Ninhydrin may be used in conjunction with DFO; however, DFO must be used ﬁrst. Fluorescence examination. Using lasers, alternative light sources or ultraviolet lamps on untreated surfaces may yield prints. Various naturally occurring chemicals and contaminants present in latent prints ﬂuoresce without treatment with laser-sensitive dyes. Although the chance of ﬁnding autoﬂuorescent latent prints is limited, the ease of the procedure suggests its use. Gentian violet or crystal violet. These dyes, which produce a purple color, stain fatty components of latent prints and are especially effective when used on the sticky side of adhesive tape. The material is toxic and appropriate laboratory precautions must be taken. Using a laser increases the sensitivity of the procedure. A yellow-orange light source yields the best results, e.g., a copper vapor laser at the 578-nm line. An alternative dye, Basic Fuchsin, yields good results with green excitation and has an absorption maximum at about 500 nm (Figure 6.7). Iodine. Iodine is one of the oldest methods of visualizing latent prints on porous and nonporous substrates. The technique is simple to use; however, iodine vapors are toxic and corrosive and the reaction is not permanent. Methods have been introduced for ﬁxing prints developed by iodine fuming, e.g., 7,8-benzoﬂavone, which also increases sensitivity. Ninhydrin solution. Ninhydrin is another technique for use with porous surfaces, e.g., paper, cardboard, wallboard, and raw wood. Ninhydrin reacts with amino acids to form a purple-colored compound called “Ruhemann’s Purple.” The reaction is speeded up by means of humidity and elevated temperatures. Treating with zinc chloride solution and viewing with a laser improve sensitivity of the techniques. Background ﬂuorescence may be overcome by using cadmium nitrate solution cooled to liquid nitrogen temperatures and viewed with a laser. Modiﬁcations to the chemical structure of ninhydrin have been

© 2004 by CRC Press LLC

Figure 6.5 Latent prints can be developed using a combination of cyanoacrylate, or superglue, and ﬂuorescent powders or dyes that can be visualized under ultraviolet light, laser, or alternative light sources. (A) and (B) are latent prints developed on multicolored, glossy-coated papers. (Zurich Cantonal Police, Forensic Science Department.)

synthesized and show usefulness under certain conditions. The importance of these analogues is that they ﬂuoresce at different wavelengths and provide a way to overcome background interference from certain substrates.

© 2004 by CRC Press LLC

Figure 6.6 (A color version of this ﬁgure follows page 256.) Using a humidity cabinet speeds up the ninhydrin reaction to proteins found in ﬁngerprints. (Los Angeles County Sheriff’s Department.)

Physical developer (PD; also called stabilized physical developer, or SPD). PD is a silver-based solution used as a substitute for the conventional latent print silver nitrate procedure. PD is useful in detecting latent prints on porous surfaces that are wet or have been wet, e.g., paper, cardboard, and raw wood. The technique may be used following ninhydrin. PD reacts with components of sweat and appears in shades from gray to almost black. PD-developed prints are preserved by photography. Silver nitrate. Silver nitrate solution reacts with chlorides in prints, but with the advent of PD it is not in widespread use. It may have some application on raw wood; however, the background staining of the substrate may cause problems in photography.

© 2004 by CRC Press LLC

Figure 6.7 (A) Adhesive-backed tapes are an excellent substrate on which to locate ﬁngerprints. The difﬁculty is removing the sticky tape from surfaces. Denis E. Kebabjian, a forensic scientist with the New York State Police laboratories, developed a simple technique for removal by using liquid nitrogen (New York State Police, Albany, New York). (B) Gentian violet is a technique sometimes used to visualize latent prints on the sticky side of adhesive tapes. (Zurich Cantonal Police, Forensic Science Department.)

Small particle reagent (SPR). This is a wet process for developing latent prints on wet surfaces. The reagent is a suspension of molybdenum disulﬁde particles prepared in a detergent solution. Molybdenum adheres to lipids found in prints as a gray deposit. The process works well on nonporous surfaces, e.g., plastic bags, wax paper, glass, and painted surfaces, and may be used effectively on water-soaked ﬁrearms. Visible prints may be lifted and/or photographed.

© 2004 by CRC Press LLC

Sudan black. This process is used on nonporous articles, e.g., glass, plastics, and metal. Usually less sensitive than SPR, it may be the method of choice if the substrate is oily or greasy. Sudan black reacts with the lipid components of prints and stains them blue-black. It is messy to use and not effective on dark-colored objects. Superglue or cyanoacrylate fuming. Superglue is used on nonporous surfaces to produce visible prints that are white. The visible prints may be dusted with powder, photographed and lifted, or washed with laser-sensitive dyes such as Rhodamine 6G and others, and viewed with lasers or alternative light sources. Superglue is one of the easier procedures to use; however, in some instances, other latent print visualization techniques may yield superior results (Figure 6.9). Vacuum metal deposition (VMD). VMD is an effective technique for most smooth, nonporous surfaces, e.g., plastic bags, plastic packaging material, and other smooth surfaces. The major drawback to vacuum metal deposition is that the equipment is expensive and the sample chamber of the vacuum coater is not very large. The procedure evaporates gold or zinc in a vacuum chamber and a very thin ﬁlm of the metal is deposited onto the latent print, making it visible. Lasers and Alternative Light Sources The word laser is an acronym for light ampliﬁcation by stimulated emission of radiation. The use of lasers and other alternative light sources has become a very important adjunct to locating and visualizing latent ﬁngerprints as well as other types of physical evidence such as trace evidence and certain types of biological evidence. Several types of lasers and so-called “alternative light sources” (high-intensity arc lamps) are in current use. No light source is best in all forensic applications. Several factors need to be considered in choosing the type of high-intensity light most suitable for use in a forensic laboratory or for ﬁeld applications. Some of the factors that must be considered are: cost, color of light or wavelengths available, light intensity or power output, portability, voltage requirements, safety, available service on an emergency basis, and the ability to use the unit in other forensic applications. Cost is a factor to consider because none of these devices is inexpensive. Some require special setups and workspace remodeling, e.g., darkened work areas to take photographs, laboratory sinks and fume hoods to handle light-sensitive dyes, power requirements, plumbed in water to cool the unit or additional units to recirculate coolant to the laser, liquid nitrogen for use in certain laser procedures — the list can be formidable and must be considered when budgeting for a unit. Other costs include maintenance and purchase of component parts that must be replaced from time to time. Not all devices are suitable for forensic latent print work. The wavelengths of the output,3 as well as the light intensity or power output, is important. Initial studies using lasers for latent ﬁngerprint detection used an argon ion laser and, later, copper vapor and portable neodynium:yttrium aluminum garnet (Nd:YAG) lasers. The working frequency of these lasers determined the laser dyes and visualization techniques that were ﬁrst developed. Alternative light sources such as xenon arc lamps seem to produce comparable results and have become more available. Some lamps have broad light frequencies (250 to 1100 nm), although their light intensities are not as great as some lasers. Alternative light 3

Some lasers and alternate light sources can be varied to produce different wavelengths of light.

© 2004 by CRC Press LLC

Figure 6.8 (A color version of this ﬁgure follows page 256.) The vacuum metal deposition places a thin ﬁlm of gold followed by a ﬁlm of zinc on latent prints left on smooth surfaces such as plastic bags. VMD is a very sensitive technique for ﬁngerprint development on nonporous and semiporous surfaces. (Los Angeles County Sheriff’s Department.)

sources have the additional beneﬁts of being less costly and more compact (thus, more portable) than some lasers. Safety is a concern with lasers and alternative light sources. The high intensity of the light can cause eye fatigue and eye damage. Persons working with these tools should be required to wear appropriate eye protection to minimize any damage. Image Processing New technology is being used to enhance latent prints that heretofore were of insufﬁcient

© 2004 by CRC Press LLC

Figure 6.9 Latent prints developed using cyanoacrylate or superglue on a pistol. (Los Angeles County Sheriff’s Department.)

computers precluded the use of such technology in most crime laboratories. Major advances in the computer industry and the resulting proliferation of relatively inexpensive Pentium class computers have placed image processing technology within the budgets of most laboratories. Latent prints are examined by means of a high-resolution video camera whose output signal is fed into a computer. Unlike the human eye, the computer is capable of distinguishing among the hundreds of shades of gray that show up as varying degrees of density captured in the image. The computer in turn can process the digital image in several ways. The image can be shown in reverse video (equivalent to a photographic reversal or negative) or in color. This is particularly advantageous if the print is on a textured surface that makes it difﬁcult to examine because of the background pattern interfering with the ridge detail of the print. Various light sources — visible, infrared, ultraviolet, high intensity, laser, ﬁltered, and unﬁltered — give considerable range to latent print identiﬁcation. Digitizing images along with readily available computer software gives excellent results. Automated Fingerprint Identiﬁcation Systems Automated ﬁngerprint identiﬁcation systems (AFIS) represent the single biggest advance in ﬁngerprint identiﬁcation technology. Heretofore, the ability to compare a latent ﬁngerprint discovered at the crime scene with a criminal ﬁngerprint database was, for all intents and purposes, impossible. The amount of human effort to conduct a manual search for a latent print against several million inked prints is astronomical and prior to AFIS was simply out of the question. Cold searches or searching a database of several million prints for a single latent found at a crime scene is a daily occurrence. Even more staggering, the search of prints on ﬁle in an AFIS database only takes about 10 minutes.

© 2004 by CRC Press LLC

Figure 6.10 The polylight is one of several alternate light sources in use today in modern law enforcement agencies.

AFIS has revolutionized the way police departments search latent prints for matches. At one time, it was not uncommon for some crime scene investigators to dust low property value crime scenes to placate crime victims who wanted the police to do something. The effort put into dusting a scene seemed to give victims a feeling that the police were doing something. In only a small percentage of cases would latent prints be matched to those of a criminal. Some police administrators even questioned the value of going through the effort of trying to locate ﬁngerprints in low property-value, residential burglaries and automobile burglaries. AFIS has completely changed that way of thinking. Simply stated, the more AFIS quality latent prints collected at crime scenes, the greater is the chance of identifying criminals by automated ﬁngerprint identiﬁcation systems. Several AFIS technologies are in use today. The main drawback at present is that they are not compatible to one another. Prints stored electronically in one state’s AFIS database cannot be searched by a system sold by another vendor. The only way around this shortcoming is to input the latent, or a copy of the latent, into the other AFIS system. Computer software and hardware to bridge that gap will improve the usefulness of AFIS technology. The quality of the inked ﬁngerprint cards used to create the AFIS database is critical. Poorly taken criminal-ﬁngerprint cards input into the AFIS database eliminate the

© 2004 by CRC Press LLC

possibility of making a correct identiﬁcation when conducting a latent print search. Because a surprisingly high number of crimes may be associated to one perpetrator, the quality of the inked ﬁngerprints and the AFIS data entry process become very important. A new alternative to taking inked prints is an electronic technique whose generic name is Livescan. Livescan technology produces high-quality print cards without the need to take inked prints. Each ﬁnger is inserted into a reader and its ﬁngerprint is captured. At the end of the process, a standard print card is produced. The next step of the process is to input the print card into the AFIS database. A shortcoming of the system is that AFIS systems are proprietary and Livescan systems cannot transfer electronic data directly into AFIS. Preservation of Fingerprints Preservation by Photography Fingerprints found at the scene of a crime should be preserved by photography when possible. This procedure has many advantages. Photography leaves the objects intact so that further photos can be